IMMUNOLOGY 2009-2010
Classical Alternative
Glycolysis Oxidative metabolism via
vlaHIF-1a STAT6 and PGC-1|i
DEVANGNA BHATIA
Topics for the examination in immunology (third year 2009/2010)
/\. Mechanisms of the innate immunity: overview, PAMPs, PRR
yi. Phagocytosis. Cells involved in the process of phagocytosis. Stages of phagocytic process.
t/3. The complement system. Classic and alternative pathways of activation of the complement system. Clinical significance of the complement system.
'^4. Inflammation. Initiation, regulation, consequences for the organism. Treatment of inflammation.
Js. Interleukins and other cytokines.
1/6. Antigen. The basis of antigenicity and immunogenity. Epitope, Hapten.
/J. Antigens of medical importance: Antigens of microorganisms. Allergens. Auto-, alio-, and xeno- antigens. Superantigens
HLA system, structure, genetic aspects, clinical significance. y 9. The role of the HLA system in immune reactions. ^ylO. Primary and secondary immune reaction. Adjuvants. ^,11. Cells involved in the immune response. ^12. Primary and secondary organs of the immune system.
3. Clonal selection theory. Rearrangement of immunoglobulin genes , •
yl4. B-lymphocytes, production of antibodies, isotype switching ©ij^'^j v' j/l_5. T-lymphocytes, Th-cell.subsests, their effector function l/16. CD8+ cells, effector function yll. NK cells , -48. Interferon
yi 9. Immunoglobulins, structure, function. Isotypes, idiotypes. L/20. Monoclonal antibodies. Production, properties, therapeutic and diagnostic use. yll. Reaction of antigen and antihody in vivo. Consequences of this reaction in.vivo. yl2. Mucosal immunity.
P~/23. Regulation of the immune system. Th, Treg cells, Idiotype-antiidiotype network,
ii/24. Immunity to viruses. Mechanisms of the host defence. Immunopathological consequences of the reactions against invading organism.
.^/Is. Immunity to bacteria. Mechanisms of the host defence. Immunopathological consequences of the reactions against invading organism.
1^6. Vaccines, vaccination.
^Primary defects of antibody production, T-cell deficiencies, SCID. Clinical manifestation, diagnosis, treatment.
.2,§-rl)eficiencies of the complement and phagocytic system. Hereditary angioedema. Wiskott-.   Aldrich syndrome, ataxia telangiectasia. Clinical manifestation, diagnosis, treatment.
.29. Non-AIDS secondary immune deficiencies.
v/3o. HIV-disease, pathogenesis.
w/31. HIV disease - clinical manifestation, diagnosis
¥1. Passive immunisation. Immunoglobulin derivates.
J}&- Anaphylactic shock. Immunopathological mechanisms, diagnosis, principles of treatment.
34. Atopy. The role of IgE. Mediators of the allergic reaction. Early and late phase of type-I immunopathological reaction.
^y#5. Diagnosis and therapy of atopic diseases.
^ ^36. Delayed-type of hypersensitivity. Tuberculin test. In vivo testing of T-lymphocyte function.
Jyi. Immune complex-mediated immunopathological diseases.
^•8. Autoimmune reactions; mechanisms of triggering the autoimmune reaction. Genetic and environmental influences.
p^J$9. Immune tolerance.
40. Laboratory tests for the detection of autoantibodies. Antinuclear and other clinically important v   autoantibodies. i^*"*^***^
J±\. Transplantation immunology. Organ transplantation. Bone marrow transplantation.
! 42. Immunological aspects of blood transfusion. Polysaccharide and protein blood group antigens.
^   Adverse reactions to transfusion.
hC%f^' mrauine interactions between mother and fetus. Immunology of reproduction.
. 44. Immune system and tumors. Protective mechanism against tumors. Immunological diagnosis and treatment in oncology.
^4s. Immunity in childhood and in elderly.
/AS. Manipulation with the immune system - immunopotentiation, immunosuppressive agents. \f %1. Serum. Classic serological reactions: Agglutination, precipitation.
Immunoassays: ELISA, RIA, Immunofluorescence. ^9. Lymphocyte subsets determination ^J^. Paraproteins, detection, clinical significance
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Mechanisms of the innate immunity: overview. PAMPS, PRR
The nonspecific innate response very quickly recognises most foreign substances and eliminates them. It is alway. present and ready to recognise and eliminate microbes, It does not react to non-microbial substances and has no memory. It frequently eliminates microbes before the specific immunity becomes active. ^     , ~~ *
Receptors are encoded in the germline, and are not a product of recombination of genes px*"tf
Basic components of non-specific (innate) defence; L iM,\i^^^V j "*
^: -i**-T£"; Win Irs ■'.-, Vc^ii" *    Hr-r :■
• Non Specific barriers **"
• Anatomical/Physiological
» Acute phase reactants and Inflammation C           | jS^vt£i
• Complement/lnterferons/CRP 1 i xi   jh^-t^T J-j- M,u? . innate cells 1     < < 1
• PMN/Macrophages/NK ceils ??? .   -.^/iVv;.;.    ^ ^ /'j',.^- ' ••   * ^
Non S»edflc barriers: Anatomical/Phvslolosical <xtW fc^^|^ll?^ > (V W «, >
tv   ^ts a resistant barrier because of its outer layer consisting of keratin, which is Indigesttbfe.for most-micro-organisms. The dry condition of the skin and the high concentration of salt of sweat are inhibitory or lethal to:mapy-pther rriicroorganisms. The sebaceous secretions and sweat also contain bactericidal and funglcldalia^yjacldsKThe;sticky m^ tract act as a
trapping mechanism for Inhaled particles, the cilia push thesecrStionsto oropharynx so thatthevnaje^wallowed and the acidic secretions of stomach destroy most of the microorganisms. N,fs.aJsecret4p^s^n^saliva:Cont3inmucopolysachiarldes capable of blocking virus. The washing action of tears and the flushing of urine afe^fe'ctlveo^topTng^vaslon by microorgaVilsms^he'natural bacterial flora covering epithelial surface are protective in a number of w^y^he[rprese^elusej^n|che that cannot be l/sed by,a pathogen, they compete for nutrients, and they produce by-products that inhTbitJtrfp growth of oWeroreanisrns ; 1
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Cells of the innate Immune response:
The innate leukocytes Include: Natural kt)l€fjcelts, ma|t\celisr:eosinophils?;basophils'. and the phagocytic cells including macrophages.
lating pathogens that might cause infection
Natural Killer Cells: They play a majoFrdleln the rejection'^ The cells kill by releasing small
cytoplasmic granules of proteins called perforin arid grarizymelhatcause'the target cell to, die by apoptosis.
Mast Cells: When activated, ma'stcells rapidly relea?^hWa(it^?isiiBBRI'n:S&s>,rlch in'hi'stamine and heparin, along with various hormonal jjh   Jjajj&and cytokines into4hQ'.e^y1|onment. Histamine"dl|ale§;bl^og[^|§^^causlng the characteristic signs of inflammation, and
recruits neut
Eosinophils: contain small grajn^jfe^l^^trjexpljm^rcyJtoplasm, wpicjp6jgaj0j;nany chemical mediators, such as histamine and proteins such as eosinophil peroxidasefn^onAcf^ and major basic protein. These mediators
are released by a process called de'granulation.followihg activation' ofthe 'eosinophil, and are toxic to both parasite and host tissues.
Basophils: Basophils appear tn;marYy^ those that cause allergic symptoms. Basophils
contain anticoagulant hep3riri,whlcr)WeyenTs'd quickly. They also contain the vasodilator histamine, which
promotesblood flow to tissues. Basbpnllsihave prbteIn:receptors on their cell surface that bind IgE,- an immunoglobulin involved in macropgj^siM^efense and alJ|^|^^i'^^MpJg|^g^^^^iat confers a selective response of these cells to environmental substalfce^rolr^rfSple, ppllen!pjot^nsjof helminfrffntlleffilRecent studies in mice suggest that basophils may also regulate the
Macrophages)';^ which are able to move outside of the vascular system by moving across the cell membrane
of capillary vessefla^ cells In pursuit of invading pathogens. The binding of bacterial molecules to receptors
oh Selurface 0f a macrophage'ffig^rs^Jc^erigulf and destroy the bacteria through the generation of a "respiratory burst", causing the release of ^active oxygen species.Pathogens also stimulate the macrophage to produce chemokines, which summons other cells to the site of infection. '?ij«pS|«K^1to»
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Neutrophiisi.aJpng^ are known as granulocytes due to the presence of granules in their cytoplasm.
NeutrbphMs'a'rS ihe.most atunya'Hf ^peif pltagocyte, normally representing 50 to 60% of the total circulating leukocytes, and are usually
rhp firef-'reilc'trt arrive at the> <ii!-p nf itn Infortinn
Dendritic cells: these are phagocytic cells present in tissues that are in contact with the external environment, mainly the skin/ and the '-x Inner mucosal lining of the nose, lungs, stomach and intestines, They are named for their resemblance to neuronal dendrites, but dendritic : cells are not connected to the nervous system. Dendritic cells are very important in the process of antigen presentation, and serve as a link between the innate and adaptive immune systems.
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Pattern recognition Receptors (PRRl on phagocytic cells are soluble molecules that can recognise PAMPS (pathogen associated molecular' patterns, such as endotoxins, mannose, double stranded RNA, etc), leading to inflammation
TOLL-like receptors are surface or intracellular receptors recognizing various^MpSvJhey are expressed on dendr|tlpxe]js_/:macrophages, granulocytes, epithelial ceils. They induce activation of these cells, which cäjgia^tpjKilling-of.the^rnlcrobeSi inflammation^.tissue;*: remodelling, and enhanced antigen presentation. jJlOo^ml. ^B^^^^^^^^^^P^*    ^ v&$jjy%ö&hcff&»
Signals generated by engagement of the toll-like receptors activate transcHltjBniRÄorsthat^sttmulate expressionofgene^sencoding cytokines, enzymes and other proteins involved in the antimicrobactenai functlonsiof activated macrophages and dendritic celts.
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Phagocytosis. Cells involved in the process of phagocytosis; ; Stages of phagocytic process.
Phagocytosis is a process by which certain ceils of the innate Immune system^includlng macrophages and neutrophils) engulf large particles {>0.5um diameter) such as intact microbes. The eel! surrounds the particle with extensions of itsplasma membranejiy an energy and '■■■■^m cytoskeleton-dependant process, leading to formation of an intracellular vesicle called a phagosome; whichxontams the ingested particle.
Tvoes of phagocytic cells: .gggy^-r
- neutrophils (most typical, first to respond, die after few hours) ^-Jpp1
- macrophages (derived from bone marrow, ingest microbes and survive fóra long period)?
- dendritic cells (mainly non-activated cells, after activation they lose most of their.phagocytic ability) -^tc z~ \
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Note: In tissues, monocytes are differentiated into macrophages. Blood monocyte's ahdljssue.macrophages are two stages of the same ceil lineage, which is often called the mononuclear phagocyte system. ^!$^£&°*>-£iiL-j- a
Th Jvo types of circulating phagocytes, neutrophils and monocytes, are blood cellsthatare fecruitecCtothe sites of infection, where they recognise and Ingest microbes for intracellular killing , ...........• •  > ' • >.
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Neutrophils are the most abundant leukocytes in the bloodjinresponse to infeotions, the producJlojV of neutrophils from the bone marrow increases rapidly, and their number rises to 20 000 p^uloftblood. Monocytes are less abundant wtth-SQOp 1000 per ul of blood. They too ingest microbes, but unlike neutrophils they can lastrforilong perlodsivln the tissues; they differentiatejnto macrophages. Macrophages produce cytokines that recruit and activate IeukocytesfSrheysecrete growth;factors and enzymes tRakfunction to repair injured tissue and
replace it with connective tissue.
Differentiation of Macrophages: -Kupffer Cells (liver)
- Alveolar macrophages (lung) ;
- Microglia (CNS)
- Osteoclasts (bone)
- Peritoneal Macrophages (peritoneum)
Extravasion of Leukocytes;
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Leukocytes are in circuiation^butforrPhagocytosis they must enter.jtHe tissues
Rolimg
4ntôsnn ^CtivatioTi
ratable,: adhsáion
Migration through ^'endothelium.:.;-?.
_ _ ._3
1. Leukocytes Ijnk-tojSelectin (cel('adheslon molecule on endotheltaj Sells)" and roll over the endothelial cells. ^ ey^of^i
2. Integrin on;thelurfacejoftthe;leukocytes is activated:caqsmg stable adhesion between the leukocyte and endothelium. ^^">,
3. Leukocytes migrateihrough gaps between theiendotheIialcellsand:rnove to the extravascular space.
Leukocyta
Chemokine Satectin
mtágriii
Oow-affimty state) -3elefitin Jigand
Integrin (htgh-affinity state)
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P'rotôo-giycars f' &
Kí) / X Cytokines (TNF, IL-1)
Integiín llgand
Chemokínes
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Macrophage
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Fibrin and fibfůnectin (extmcellutar matrix)
& Elsevtef Ltd. Abbss & Uclitman: Basic Imfiiunoit>Qy 2E www.studanteonsult.com
If an infectious microbe breaches an epithelium and enters the subepithelial tissue, resident macrophages recognise the microbe and. ■ respond by producing cytokines. Two of these cytokines, TNF and IL-1 act on the endothelium of small vessels at the site of infection They stimulate endothelial cells to rapidly express two adhesion molecules, E-selectin and P-selectin.
Circulating neutrophils and monocytes can bind weakly to selectins. The neutrophils become tethered to the endothelium, flowing biood disrupts this binding, and the bonds reform downstream, and so on, resulting In the 'rolling, of leukocytes on the endothellal.s'urface:^
Leukocytes express another set of adhesion molecules, the Integrtns, because they 'integrate', exfrinstcslgnais into cytoskeletal alterations. As these cells are rolling on the endothelium, tissue macrophages that encounter the microbe/and endothelial cells responding to •.• . <; macrophage-derived TNF and IL-1, produce cytokines called chemokines.
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Chemokines stimulate a rapid increase in the affinity of the leukocyte lntegr!ns_for their ligands on the endothelium. At the same time, TNF and iL-1 act on the endothelium to stimulate expression of ligands. The firm blndfng7of_inTegrms to their ligands stops the rolling leukocytes
on the endothelium. The cytoskeleton of the leukocytes is reorganised and.tRe:cells are spread oat on the endothelial surface^
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The sequence of selectln-mediated rolling, integrin-mediated adhesion and^chemokine-mediated motility leads to the migration of blood leukocytes to an extravascular site of infection. The accumulation of leukocytes-at tl\e:site of-mfectlon: with vasculnridlalatloTyand increased permeability of fluid and proteins In the tissue is called inflammation * ~
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ÄÉÉIII
Chemotaxlns + Chemotaxis: factive movement of cell towards something, according to chemlcajs)*;
- attract phagocytic cells jj *
- can be products of destroyed cells
- C5a !s very potent
- IL-7, IL1
- leukotrines-attract leukocytes in allergic inflammation.!
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_§gQS^,__ ___
•j   <,r^Si--^ J < ^ iJ^-S^tj^S .- __________..............._______
An opsonin is any molecule that acts as a binding enhancer foftheproces^fphagocytosls; for- example; by coating the negatively-charged molecules on the membrane '   ^^J^Pj**^ >'■'''' \ * J
*   Specific: IgG, (IgM only indirectty;by activation of the complement system)
Non specific C3b fibronectin^"13" -J**^- j^n . i
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Stages of Phagocytosis: Mrwmwor--*
1. Microbes bind to phagocyte receptors (e g mannose receptors)    ^ ^
2. 11 lagocyte forms pseudoppds(extensions of phagocyte plasma membrane) that engulf the particle.
3. Microbe is internalised Into a phagocytic vesicle^ontamlng microbe--the phagosome.
4. Fusion of phagosome;with-ly5osome;xontainingenzymesj-to,form a phage
5. Activation of phagocyte leids to ^isffir^
- killing of mlcrobeby lysosomal en^rj^ejWphagoIysosome''/r '
- killing of microbe by reactive oxygenqnt^rnetfiates and nitric oxide
^olysosome.
6. indigestible and residual material.is;reir)oved by exocytosis
t- 5
Killiňŕméčhantsms of phagocytic cellsm- —=3«\fefe,C^■; /Oj - rMčtľvé-metabolites ofoxygeni(H202J hydroxyl radical^etcjj reactive nitrogen intermediates (NO, N02)
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Vlys^ôsyrňe'cleavescellwalísbf&í^acfél'la^í^: SWfr - iaSfôfélŕihblnds Fe and vitamin%Í2|ÍÉA;í0^' -defensäns: antimicrobial polypeptides' -'
6 QnzijY*ej$ Ä&fitfattJ cJh£<^ - Htfcc oxide £iýittmý: Catjhu^e
NO
Activation of the Complement System; Classical pathway:
- Complexes (IgG-antigen, IgM-antigen)       , /                 _ ( ,
- C-reacttveprotein-—^ pUd^odUoi^W &A ^        pec f^diMm(dU -t^^v^^H^t^ Alternative pathway                              ' ~ J^lJ_ _
- Lipopolysaccharlde of G-bacteria * -
- Celi wall of some bacteria
- Cell wall of the yeasts il ^^^0-?^
- Aggregated IgA Lectin pathway:
- Mannose and other sacharides
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Clinical Significance: it _ ^£^^,4.
Inherited deficiencies of complement proteins are the cause of human diseases ' ^
• Individuals who lack complements C5 through C9 are susceptible to meningococcal mfectiohs&hesecomponents are responsible j   for destroying the organism bactivJJ ' ^  ^ ^
• C3 deficiency results in profound susceptibility tojnfectlonsandiis usually fatal in earlyljfe'&'i'^wj*'
• C2 and C4 deficiencies are associated with an increaselncidence'of immune complex diseases; jesembUns systemic lupus erythematosus. 0 i>> depict *ftJrW
• C9 deficiency results in Increased susceptibility to Neisseria Infections::'.' ^ 1 ./f t~       r       s h«
Tests for complement system ^ <~    ; ^ ^ ^ j1*
• in Infection, the components decrease lnserum as the complement system is activatedrapi?^
• Acute phase proteins are increised due to infhnirnition .w., .
• We measure C3 and C4 by turtydimetry (by ability to<scatter laser,light)s;;
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The complement system. Classic and alternative pathways of activation of the complement system. Clinical significance.
This is a biochemical cascade that helps to clear pathogens from an organism, it ts part of the innate immune response; |t isnot adaptable!; and cannot be changed over the course of an Individuals lifetime, however it can be recruited and broughtjnto action by.theadaptive immune system.
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The complement system serves three functions in host defense:
1. C3b coats microbes and promotes the binding of these microbes to phagocytes/thus, microbes that are opsonised with complement'' proteins are rapidly ingested and destroyed by Phagocytosis. ^^"^^ogj^i   ( -r-   Ss^y^ _^
2. C3a and C5a are chemoattractants for phagocytes, and they promote leukocyte,recrultment(mflajnjTnation}at thesiteofcomplement
activation. («.^) ^WifflS^iW1 « fb\^i ^
3. Complement activation culminates I
disturbing the permeability barrier and causing either osmotic lysis or apoptosis.of t{ie;i
culminates In the formation of a polymeric protein.complexthatinserts:mto theTTilcrobial cell membrane, y barrier and causing either osmotic lysis or apoptosis of the microbe      * , *   " '
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ALTERNATIVE PATHWAY: }n;|*dx4 fcy-^?0*ckK^^^^r*S
1 '■1 "la. C3a is a.sfgnaiTlingJriblecUje (triggers i
' hydrotyslslorsiteindSco'vafe^ of a micTpe^pp
C3b binds factor B, which is cleaved in to Ba and:Bb;byfactorTBjiG3bBb.complex is formed; which Is'a Cuconvertase (this is stabilized by properdin). C3 convertase creates many more C3b;moJecu|espthusJimplifylng the pathway; C3b can bind to C3 convertase. to form C5 convertase. ^ CvS^V i^rfl-fu/«-*U   fA fMi#J(jkW>
An overview of the three pathways of the complement svstem'fgStg^ *r   $ ,
C3 in plasma Is cleaved to form C3fa and C3a. C3a Is a-sJir^ljif^iblecUle^trlggers mfiammation. binding receptors on nearby leukocytes}* C3b is unstable and is either inactivated by hydroiyjfsjji^ of a microbeS^^
CS convertase cleaves C5 Into C5a and C5b,:wh|ch, initiate"^tn^IaTe^tages-ofcomplement activation
C6 binds to C5b. C7 then binds to C5bC6;~a.ndiG^1s-hydrophobic scfl^anchors the C5bC6C7. complex into the lipid bilayer of the cell membrane. C8 then binds to both the CSljCfiC^omple^lriSlhe lipoid bilayer tf
C9 polymerizes the C5bC6C7G8 site, forming a membrane attackxomplexi(MAC). The:MAG pore allows entry of water and ions, causing
os    fic swelling, rupture andjcell(death.
Devangna says:    tJV^-^;^^>i, ^bh^^
If there is no factor B, then c3b is'ftot stable and factor I afong with H, cause inhibition,..makes sense? whereas if B Is present it stabilises G3bGmd{5(eye'nts Inhibition by FacH Fqc H and B compete fr the same site on the C3b molecule.
■ it stabilises;G3b and pxeyenjs-lqhjbition by Fac H Fqc
CLASSIC PATHWAY: iUH d&$*tjSr! IF33^
0      ~Ss*^_tp0_    -        \ J^
Antibodies bind to antigens on the microbe.Gl binds to Fc regions of the antibodies. CI is made up of one molecule of Clq, two molecules of Clr ancRwo molecules of ClsiBindingitojrie'antibodies results in activation of Clr and C2s proteases.
iltM|fi|WffwiTiiTrilT"ii ii'intii|-iTh 1 hdC4t
Active Clr-Cls then cleaves C2 Into C2b and C2a, forming£4bC2b which is a C3 convertase (The remaining steps are the same as the active
and C4b'. C4b'attache'stb
Active Clr-Cls^cleaves C4 into C4a and C4b'. C4b^tta^tes:to tjie surface of the cell. Li^kcVtie-*-
pathway). ^
LECTIN PATHWAY: ^,
The m'annose-blndmg lectin receptor binds fomannose and other sugars. It forms a complex with MASP-I and MASP-II (mannose-binding lectiri^associated serine protease). fylASR-l and MASP-II are'activated, and cleave C4 and C2 (similar to classic pathway) to form C4bC2b - C3 convertase (The remaining steps are the same as the active pathway).
Inflammation. Initiation, regulations, consequences for the ; organism. Treatment of inflammation. ^fc*"*'
Inflammation is the complex biological response of vascular tissues to harmful stimuli £^uch as^
Inflammation is a protective attempt by the organism to remove the injurious stimuli as weilYsirjItiate the
^'^^^Mfe^. " Inflammation can be classified as either acute or chronic. Acute inflammation is the initial response of the 'bdd^tcVhVrmful stimuli and is
achieved by the increased movement of plasma and leukocytes from the blood in'tni-he Injured tl«up<;.
^ffe^febti «r hr*x^«ft3<^s#B- W^VVvo&uoi ^t\iud^^w<_ Prolonged inflammation, known as cfi^gjnfJwiWMort; ISads to a progressiveshiftinthetypeof cellswhich are present at thesiteof
inflammation and is characterized by simultaneous destruction and healing of the tissue from the inflammatory process    * [~
Inflammation is initiated by changes In blood vessels that promote leukocyte recrultméntbltT^ dolor, rubor, and calor. ""^1      -^eSSr     * *
Initiation of Inflammation: k<-wr
Activation of macrophages by IFN-y R4T\,. I| * ^/flM'fe-,
Activation of NK cells by g&m \tr^~ * f^^^   " d^tfctiC ^eacfe
Release of cytokines and chemokines that stimulate migratton of leukocytes*-; ••u ■' ^jgl*? Ijv' ^"tf" Damaged tissues release histamine, which increases local blood flow _ije££K. k' .
Histamines cause capillaries to leak, releasing phagocytes-and clotting factors Into the wound ■
Platelets move out of the capillary to seal the wourid^^ffi^ -2, ,    ^ ^^l,, f J- Vs5^9
Local consequences: j."*^- ' ,,
Increased blood flow to affected area (mbor and calor):fteeruitrrient of phagocytes to affected areaf particularly neutrophils and macrophages (due to secretion of cy^nes andxhemokines).An elevated presence of neutrophils is evidence of Infection. Increase of vascular permeability leading to entf^fbf soluble molecujeyrom the plasma'jeads to sv/e)jingJtumor). Chemical mediators released by granulocytic cells such as mast cells, eoslhophlfs.and basophils stimulate" nervesand.:caus|,palh.^^rO^*^ ^-\vu ^
Serum levels of acute-phase proteins increase during inflammation. Jhey are producedby the liver after stimulation by IL-1IL-6, and TNF. C-    ttive protein binds phospholipids.^ membrane of bacterial^?— ^&&jy&^!$>\5 CpSOWSorfcdoiA \
TreatmBntof,nf,ammat,o-n - - ^ ^ * f^J,
Glucocorticoids -decrease inHammatioiT^/,^,^ UwC - <x P&$&r^.6i\t t sUg^k \ xju^j^ vjfo"
Non-steroid anti-inflamrnatorylo'rugsprevent cellljjoduclng prostaglaridins (main chemical mediator of inflammation) ^ ^ '' 'i Antihistamines ^T ^^'^M'^K^K      A6*WlA ,fk5U^)
Monoclonal antibodies against lnfia,mmatory1cyto1anes and adhesionTnolecules
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Interleukins and other cytokines
Cytokines are secreted soluble proteins that function as mediators of immune and mflammatory.reactions;lnmnate,immune responses:-cytokines are produced by macrophages and dendritic cells. In adaptive immune response/ cytoklrTesare mainly produced by helperl^s lymphocytes. "* ^ ^ ^   4 r
Most cytokines act on the cells that produce them (called autocrine actions) or on adjacent cells (paracrine actions). In innate Immune
reactions against infections, enough macrophages may be activated that large amounts of cytokines areprodiiced;vand.they may be active distant from their site of secretion. ^ jjr'V*"—     ^^-4 =r
.1» TW^^i ——
Cytokine therapy:
re*
IFN-y down regulates.the iL-4 production and reduces the development ofJgE i-esponsěsg^-j^Vgj^-IFN-a: leukaemia, tumours, chronic viral hepatitis XM^hň^MS^^^é^ ^
IFN-b: multiple sclerosis il-2: tumours: carcinomas, melanomas
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|> Cytokine >ikfr	Prwfcipal   k   ; r\ cpfflsourpe(s)	r%čfcal cellular target ,<
facforfTNF^|$i		ErK^ietW      aclivEdiOft (InlisíTiimbůtí. : coaguUiUon) Nůulroptilts; áCliVfiBOrV : H/poihalemus lever Liveri synthesis of ewlephasoptotolns -Muscle, tet cslabotisrn (cechowa): ■. Many celí types: apoptosl
	Macrtiptiafles, endoiheilals ce!is,son» epithelial'ceíe.i •i   * * ;	íkr^itífa^l5a^^ferfl|^Ííw(ff[.i Klřpóf>a)aíiiiE lovor Vá£:::fMš
	Macrtphngoí, cn<Jclhéllal -Wills. T fymphacylos, .. ; fibrůbtešts, piatslets	Leukocytes: chemotaxis, activůljcui •
		NK íellsiinJXasf^EfffS^® la" ^ Tffi/is TH1 áyfpSfflsaasit-i- /
Irijerfejbn^iiřŇ-^ i	MKcefis. T lyTOptioíyias ■	Activalbn ofmaeiopharas sůimilafiort of eome arrtibotly rcsponaoa
	IFN ft, Mťusrtphagea ' i FN p flbioltesiř,	
lnterteuklrHoílL-10)	Macrophages, T cella • {nwtnl/TH?)	Macicpliagua: failisbAlon of IL-12 praducbon, roíkjc^ii esfpr?wl(h3 o! cqwlmtifalarg eíid ■ díd&u MtIC molecules
	. Macrophages,' endothoIiíFi cat? fcmmCf.fiKf r               ř ^	.liver Sřn8leaí5{aa3e pfifcsjiwplélrrs^ BgUš^t^i{er*0fiTOf*^^l«f^f31|
	Macrophages, ottiois :.	NK cells. prtlrkruLon T cb!ís: pfoíifc-fatlon
Intertookinie'iMe)	Macrophages	railsan^lŤíďI^Ifn y^řnffias^^ "fTr/j"'" ■■""■"„7- ------:.T.-i-.i?lrr-.'- t.- - - ^---. .. -=.-—, v---. r^j-x
At hlghrconcentratlons, TNF promotes thrombus ^formation ontheendothelium and reduces blood «'/pressure byyascular-dialation and leaking. Severe iNissemlnatelp^bacterla.lnfections sometimes lead to a sepotentiaiiy letrTaJiClinical syndrome known as SEPTIC SHOC(<; This is characterised by low blood pressure, dlsserjrtinatedjntravascular coagulation and metabolic !dlstul"5ancea|^"early clinical and pathological ifimanifestltions'bfseptic shock are caused by very high Z levels of TNF which Is produced in response to the e bacteria.
viral infections, dendritic ceils, macrophages, and otherlrifected cells produce interferons which inhibit viral replication and prevent spread of the infection to - unaffected cells.
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Antigen. The basis of antigenicity and immunogenicitv. Epitope, Hapten. J-\ ^ < i
An antigen is a substance that is recognised by the immune system and triggers immune reactionand immunogemcity.Products of thest'fst immune reaction (antibodies, T-Iymphocytes) react with them. £  , J
{j-lijMphs- * ^ "-ur        ^" r
Similarly, an immunogen Is a specific type of antigen. An immunogen is defined as a substance that is able:to provoke an adaptive immune response if injected on its own. Said another way, an Immunogen Is able to Induce^ an immune response, while an antigen liable to v. combine with the products of an immune response once they are made. The qveTjapplrig'concepts of immunogenkity and antigenicity are thereby subtly different. According to a current text book: ^3jĚ3&3#^§fí^^'^^žzl ^        ^ ^ t- '
"Immunogenlclty Is the ability to induce a humoral and/or cell-mediated iTnmune response"
% :,. ;.'        '• .  J < :        ■ ■   . 5 v
"Antigenicity is the ability to combine specifically with the final products of the [immune response] (i.e.1 secreted antibodies and/or surface receptors on T-cells). Although all molecules that have the propertyroflmmunogemcity also have the property of i  antigenicity, the reverse is not true." 'íař'JS?^^,^*'r1lí':'A,:*''f''s'■'
Requirements:forelgnness, high molecularweight, and chernical5ómprex\ty^fe,       WšpeB&ť —
& (ZD "/<--,   ' V„S^ r
Antigens are usually proteins or polysaccharides. litis includes parts.fcoats, capsules) cell walls,.Tlageila,-flmbrae, and toxins) of bacteria,
viruses, and other microorganisms. Lipids and nucleicacfds areantlgehic onlywheňvcombined with proteins and polysaccharides. Non-
microbial exogenous (non-self) antigens can include pollen, egg white, and -protein's' from transplan^edttssues and organs or on the surface
of transfused blood cells. Vaccines are examplesio'fImmunogenic antigens intentionally admlmstered.to induce acquired immunity in the
Antigen basic components: .tidCfe^ ^^fMáS^m^i^f/?^^1^-^^^ *
Carrier part of the molecule (different chemical compositions) y' \ ' J[' l( :_{Jq\j^S   ~-=* $pWM\0 Uptsi* ^-,^30^-^
Antigenic determinant = eplptopes (5-7aa), -< ! ''1      U^ti)^' »Af       ,       <  '     J  , '   .       1 ^ r L .
An epitope, also known as antigenic determinant,ls*\he partiof-á^acromolecule that is;recognlzed by the immune system, specifically by ar>*" ydles, B cells, or T cetlsffheipa_rt gf an antibody thal^č6^r|íll;tj\e.epítbpe Is called a paratope.^ j    j ^ fa^j^n
Most epitopes recognized^by-antibodiesor|řcells can be thought of as three-dimensional surface features of an antigen molecule; these features fit precisely andjhus bipd,lo^ti^b^dJes?Exceptlons are linear,epitopes,"which are determined by the amino acid sequence (the primary structure) rather.,than;by-:the3D.shajíeJ(tectiárýstfucture) of*a protein. >'
T cell epitopes are presented on thesurface.otan-antlge they are bound to MHC molecules. T cell epitopes
presented by MHCclasslmoieculesiareiypica^Iy^ amino acids In lengths, whereas MHC class II molecules
present longer peptides, and non-classical MHC moíe_čule^áfsbípTéŠentjň epitopes such as glycolipids. Epitopes can be mapped
using protein microarrays, and withthe EL1SROT or;ELlSA^:echnlqQěs.
A hapteWlsfnaismall molecule tf^at can elicit.anipmun&respqns^only when attached to a large carrier such as a protein; the carrier may be one that also does notelicitan lmmune:iesponse;b*y!ttsel£i{trTgeneral, only large molecules, infectious agents, or insoluble foreign matter caiteljclt'aji'lmmune response.m thebpdy.) Once the~bodyjias generated antibodies to a hapten-carrier adduct, the small-molecule hapten .m'ay;§lsp'b"e;apie to bind to Jheantlbody, but it will usually hot initiate an immune response; usually only the hapten-carrier adduct can do this!. Sometimes the small-molecule hapten can even block immune response to the hapten-carrier adduct by preventing the adduct from "blndin'g'tb the antibody   MWjj ^IV*' ^
Cross reactivity refers to the ab|lityofone,m i|R f 3 yal paratope to bind with more than one epitope. Cross reactions arise because the cross reacting.antigen has an epitope which^S'^tfii^utaliy similar to one on the immunizing antigen. An example of cross reactivity in an autoimmune^cTisease is Rheumatic.Feyer/|\n|igens of streptococcus Pyogenes are similar to antigens found in the heart. Antibodies can therefore cross react" ,      , -f
6)
Antigens of medical importance: antigens of microorganisms allergens. Auto-, alio-, xeno- antigens. Superantigens.
Antigen: stimulates an Immune response against itself T j   _ "
Allergen: an antigen or Immunogen that elicits an immediate hypersensitivity (allergic) reaction:•"Allergens" are proteins or chemicals.bound*
to proteins, that induce IgE antibody production In atopic individuals. JajT   %T4        \ "      * ^ ia+i
^ —. -*-x
Common Allergens: ^ "v"       ^ ^
-pollens(grass,trees) "f^T -^^VfC *
- house dust mites ^ ^ v-ffr^Tfj, ^ ^
- foods (nuts, milk, eggs, chocolates, fruit) s-fej-i fj* ^ ^ -i**3, ~ * -pets (cats, dogs) i^ll^g^^fj^, ^J^*^
- moulds (fungi) ^g^Jfi^t—r                           "t^Td'^^ ^*
Autoantigens: antigens from the individual (self antigens) •* 1- Sj| f
Alloantlgens: antigens obtained from another individual from the same specie?(recognised arforelgn) _ j£ =u->
Xenoantigens: antigens from another species. ^i^C'4
Su^rantlgens: ^ fy&taco Ctyi dCifi <^J&ft i «?>&.
Superantigens bind first to the invariant regions of HLA Class li receptors and,T-.cell receptorf(TCR) Theycause nan-specific activation of
T-cells resulting in polyclonal T cell activation and masslvi-cyfokine release.'Th)s'jiiay lead toa severe septic shock which can be lethal.
6-bacteria: /It^l^j! ^3^t*
E. Coti and other enterobacteriae typing of stralns'ts basedsn"th,'e'diffefence" in tlirie'structural antigens: O/'h and K
O-antigen (repeating oligosaccharides)       .JS|| ^j^yjp" ^^y^t ^1^^^^   5 J^*^ 5* Found on the polysaccharide portion of the LTp^olysaccharlde ,'imp'offant forsferologlcal classification of < '  ' '
H- antigens (flagellar proteins! ^Igrf,?^ *       VJ £ *^ ~^"""-
Important in serological classification of."enteric; bacilli; only E: Coll FiavefthenW*€*SiH
K-antlgens (capsular proteins)       ^Ip^tT ffi^w    ifr * ^   *,%r i^ I
■ enteric bacilli.
Acidic polysaccharide external to cell wall' y;& \      ^ -
Shigella serotypes are organised jnto A, B, C and D-groups:based:on serologic relatednessof their polysaccharide O-antigens.
V/f    ir have both O and H antigens/but only O antigens are useful in dlstlrTgUjshing strains that cause epidemics. 01 = cholera. 2%i        '"j* ^ V %
^     Ä ^  ^   ? ^ t~ *H
Microorganisms wtth capsular 'polysaccharides j-J f^ v
Z        ~ ~ €        Jr1-    % ä
Haemophilus influenza B ^        i$=. ^
Neisseria Meningitidis ~* Streptococcus Pneumoniae ^_
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Microorganisms with surface antigens ^ +
Hppatitis"BT- j  «, m f
Microorganisms with toxoids >
piptherla "
Tetanus 11
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HLA system, structure, genetic aspects, clinical significance.
The human leukocyte antigen system (HLA) is the name of the maior histocompatibility complex fMHC) glycoprotein In humans. It is'--' controlled by genes located on chromosome 6. It encodes cell surface molecules specialized to present antigenic peptides to the T-cell receptor (TCR) on T cells. They are membrane glycoproteins that each contain a peptide.binding cleft at theammo-terminal-end.1 MHO: molecules that present antigens are divided into 2 main classes.
The physiological function of MHC molecules Is to display peptides derived from protein antigens, to antigen specific T-lymphocytes.
4
MHC CLASS i: — ^
MHC class I molecule consists of two po!ypeptide^chalns^a-3hd:P2-micrpglobuiln'. The two chains are associated noncovaiently. Only the ct chain Is polymorphicand encoded by MHC gene/while the p2-microglobulinis"inot polymorphic and encoded by other gene (chrombspmeslSj^r/ie a3 domain is transmembrane where CD8 binds.
"■5, rrM^Tt -3.-^^'    **t*t    „    ^ „ J   Jlf '
The ctl and a2 domains fold to make up a groove for peptides to bind;'MHC class )molecu!e blndspeptides that are 8-10 amino acid in length. "^^ftf" -ffc ^ »  I. >
Levels of B2jucroglobuiin are increased in patients with iffytl&ma and AIDS   is a marker of cance?ln lab tests
*4 ^
MHC CLASS n -       J5; F
Like MHC class I molecules, class?!,molecules jaretalso^n'lterodimers, but in thiVcase consist of two homologous peptides, an a and P chain, botrVof which are.encodecj inrthe MHO. Because theanhgen-binding groove of MHC class II molecules Is open at both ends whjfe the corresponding^groove on cltssl moiecuiesis closed at each end, the antigens presented by MHC class l^molecules^are longeT^generally between ;15:aridj24 ammo acid residues long. Goth the a 2 and B2 domains are transmembranepmid theB/tdomairfifwhere CD4 binds?,'
1 Jl*
Class II molecules are found ontyon a few specialized cell types, including macrophages, dendritic cells and B cells, all of which are professional-antmen-presenting cells'.fAPCs).''   ^ -t,
^  " f —T t
CLASS
NOMENCLATURE
FOUND ON"! -
■FUNCTIONS
Presentation of Intracellular Ag &\e* (AjKntSi i Presentation of extracellular Ag- ptawjoet-jtei-e f
Components of complement system
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All nucleated cells;
« C 'tfiÄ HLA-A/O/C'
II / h0<A^1^ DPa, DPb;DCta DQb,-^   Dendritic cells macrophages^ Bc< ~P DRal DRb%DRb2     ^     n^WftWU ^
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C2,C4,Bf
h     Secreted, not expressed on surface
^ V- ifc-—'        > . _ s
Genetic Aspects:
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MHC genes.are^ebdomlnantly expressedisrneaning.that the alleles inherited from both parents are expressed equally. There are three polymo?phrcClaJs;1 genes, each person-inherits one set from each parent. In Class II, each individual inherits one pair of DP, one pair of DQ, one-pair of DRa; and one or two DRb. :
The set of MHC genes present on each chromosome are called MHC haplotypes.
Clinical Significance: ^2
Various (predominantly immunopathologic) diseases are more frequent in persons with some particular HLA antigens - autoimmune diseases Itnkedto particular MHC alleles. Presence of the HLA antigen makes a predisposition to the development of the disease (increased 'elative risk) but does not cause.a disease ^"V
Particular MHC alleles may contribute to the development of autoimmunity, because they are inefficient at displaying self antigens, leading to defective negative selection of T cells, or because peptide antigens presented my fall to stimulate T-reg celts.
Disease	HLA antigen	
Rheumatoid Arthritis	DR4	
Type 1 Diabetes	DR3/DR4	
Chronic Hepatitis	DR3	
Ankylosing Spondylitis	B27     (90-100% relative risk]	Al
Ankylosing Spondylitis		
Males are predominantly affected, frequency 1:1000. It usually starts with-sacroilejtlsf.conseqtfently theA/ertebral cbitTrrin is'affected. Fibrotisation and ossification of Intervertebral Joints and filaments follows. The process leads to decreased motility andahkylbsis In the terminal state. 95% of patients are HLA-B27 positive Diagnosis ??? jM"'        r ^ } ^
it.
The role of HLA system in immune reactions     of0*** 3
The ability of T-cells to recognise an antigen is dependant on association of the antigen with either class i or class II proteins
1) Cytotoxic CDS T-cells respond to antigen in association with MHC Class I + ^ 2-^~ *       ^ "^j^
2) Helper CD4 T-cells respond to the presence of MHC Class II -      i - *Z^f T&    ft ~-~ x
MHC restriction is the ability to recognise an antigen in association with a'self MHC protein    -   fl /■
HLA Class I: bind peptides 8-9aa long, derived predominantly from proteins processed inside the cells (cytoplasm-* ER}.fBa!cteria and viruses that have Infected cells generate peptides via the endogenous pathway1 of antigen processing. MHC class l^peptTde >lnteratti with CD8+ T-cells which then kill the target ceil jg}^ ^"fLS^O /3^B|v f^> -J "t2|J(   * ~ t
HLA Class II: bind peptides 12-25aa long, derived from extracellular protelnsi^which have been pCQ'cejsed jh the acid:coijipaftments of the cell (endosomes and lysosomes). Peptides are generated in thi: ~ ~ ^ *
known as the 'exogenous pathway* of antigen processing.
this compartment.followjng the uptake: of tl)e Ag frorn outside the cell. This is
Degradation and presentation of antigens on the HLA-II molecule.??? ■s.>m,scsa«agjB«5
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initiation of antibody response In T-cell dependant antigens 1) Antigen binding to B-cell receptors delivers the first signal to the B"ce]Uj ^^si^T-p, * f
1) Antigen binding to B-ce!l receptors delivers the first signal to the BceiWj 0*^0«S^S ''    <? fhrtll
2) The helper Th2 cell delivers the second signal via theCD40 ijgands and cytokines $ V'^^^f °^
3) B cell proliferates and differentiates inlo plasma cells * ^ k L^'^&i 'f> zfo<f0-L^>^ C\>kOl~
Expression of viral antigens on HLA-I molecules iJA^ ^ t ^"IS^L ^j^ffi^S' Cftijo ^ ,
1) Proteins enter the cytoplasm of cells eithe^frmivp!iagocytosed.'rnicrobeSror:from endogenous-synthesis by microbes such as viruses, that
reside In the cytoplasm of infected cells. ^
2) Cytoplasmic proteins are unfolded, ubjquinated arid degraded inproteosomes       s - --^Nph
3) The peptides produced are then traqsportedito.the^ER, wheremiejpeptides may.be further modified
4) Peptides bind to the newly synthe|(||ci clfejJviHC Holecu'e6Clf*iip ^ ^V^^UT^ . ^ ^^c|ift».r3
5) The peptide-class I MHC complex is%ansported \p the cell surface"^ -   a %' 5
r'    "  - Of? I .0^1(0* '
Primary and Secondary immune response. Adjuvants.        '3 \
The immune response to the first exposure of an antigen is caiied the primary immune response, it is mediated by lymphocytes."called '>1: naive lymphocytes, as they are seeing the antigen for the first time and are immunologically inexperienced^
Subsequent encounters with the same antigen lead to responses called secondary immune.responsesi-thnt are usually more rapid, larger:' and better able to eliminate the antigen. £ j   -    ~* r
Secondary responses are the result of the actication of memory lymphocytes, which are long-livingJells Induced duririgthe primary tiitj$~ response. Immunologic memory optimizes the ability of the Immune system to combat persistant and recurrentinfectkjhs: because each
encounter with a microbe generates more memory cells and activated previously generated memory cells T        ^ "*
j - -        -?
The primary reaction is the Immune response occurring on the first expos^re^to a foreign materjafin the body    i ^
This reaction is by both the innate and acquired immune system, the innate acting first (non specific) and theacquired developing to
produce antibodies and T killer cells specific to the invading microorganismiiThe goal.ofrall vac^iriesls promote a primaj-yjmmune reaction
so that when the organism is again exposed to the antigen, a much stronger s"eeondary^niune:re'sJonse\yl^
immune response to an antigen is called a secondary response and it has     ^ ,^jt ~L *^  <S* ~
I        a.   a shorter lag time, ^ ^ £5, ^
b. more rapid buildup, .ftef
c. a higher overall level of response.      j^xaSfet ^   . ..^......
d. higher average affinity, ^ |^ >u J
e. utilizes IgG instead ofthe large multipurpose antibody Igivf ^ ^^J,'^    a %
^ A *  3? it1 c,|r*r5PL
A primary response lag time is usually 5-10 days wheraslecondaryfesponse Is abou^ 1 3 days *
In immunology, an adjuvant is an agent that may stimulate ihe^mmune^stem andjncreaserthe response to a vaccine, without having any specific antigenic effect in itself. The word "adjMvant^comes,from theilatinword adjuvarei^emng to help or aid. An immunologic adjuvant is defined as any substance thataTSs to acceleratei'pr.olongJorJnhance^ntigenTspeclfic immune responses when used in combination with specific vaccine antigens"' ^        ^=~L. *    iV k Au \K 0. Is l'
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It hightens the response by enhancingTiceH activation by promoting tlre:accumulation of ARC at a site of antigen exposure, and by enhancing the expression of costimulators and cytokines (that activate Trcells) by. the APGsv-sj"
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Cells involved in the immune response. Ctmos^.^"wI
The main cells of the immune system are: t« ^JfpQgi   -.<? x^C-^
T lymphocytes play a central roie in cell-mediated immunity. They can be distinguished from other Jyrnpnocyte types: suclras B céilš and "..i\ natural killer cells by the presence of a special receptor on their ceil surface called T ceii receptors (TCR)';The abbreviation T. in T cell, stands-for thymus, since this is the principal organ responsible for the T cell's maturation. Several different subsets" of T cells have been discovered, each with a distinct function.:    Hfc>^ ** cM^^ , í^iw ^       2   1 Syt<u*.t{P
- WWjwCkiUj Toi^r^O -f^q^4 é '
- Helper T-ce!!s, assist other WBC e.g. maturation of B cells {CD4) ; ^ ^      wfci )^^t\ ujv
- Cytotoxic T-ceils, destroy infected cells (CD8) J ^      -fj^ ^j**' &
- Memory T-ceils, are antigen specific -    ^^fc^W^M Jflfc^^ >
f    L1$^~   Regulatory T-celis, act to suppress activation of the:immune system1,and thereby maintain immune system t^H' homeostasis and tolerance to self-antigens I L itiť-^tOf-^pj1 (     fe. "     ^ t4ňi„r
B lymphocytes play a large role in the humoral immune response (as opposed toít^e.celiimě^iated iifwnuneresp is governed by
T cells). The principal functions of B cells are to make antibodies against antigenŠfperform:tR%ole ofÁQtfgen Presenting Ceils (APCs) and ev -+ua!ly develop into memory B cells after activation by antigen interaction P\ÍÍ£A.<A \ ^&&tyM       'ť_-V\£ltfcr ^5 ^ Wri'^tj'
Eosinophils: contain small granules within the cellular cytoplasfó which co ntaln many chemicalmediatorsrsuch as histamine and proteins c t
Basophils: Basophils appear in many specific Wnds^fl^p^p^J^ictiens^partlcvjlarly those that causB^allergic symptoms. Basophils contain anticoagulant heparin, which prevents '$%ly^Th'e^8lso contain the vasodilator histamine, which
promotes blood flow to tissues. Basophils havj^^||^^^^^ieir/cel|-surfa"ce^hat bmdlgE^an immunoglobulin Involved In macroparasite defense and allergy. It is the ^|^LC^||i^[|^^!?|onfeW:a:$e[ecfive;responie'of these cells to environmental substances, for example, pollen proteins or;helr^r^nla'n^e^^Mln^studles-mmicjfsoggest thaTbasophlls may also regulate the
„._________^.Ife
Neutrophlls: along with eosinophils aM6aJo]Dfe of granules in their cytoplasm.
Neutrophils are the most abundant type-off ^---i-*--------^.-^r-^.-^c^--      -•-—«-■■■—■—•—-------• -
the first cells to arrive at the site i
Mar--ophages: are large phag'Spyticleukocytes, which ar^rlSie^Slrno^ou^sTde of the*vascular system by moving across the cell membrane
of c . illary vessels and enjef—--------•—*•-------- --------•-J--------- ... —
on the surface
release of reactive oxyge&specleVtathogeQi?!^ the m#oppa;|FtQ'produce chemokines, which summons other cells to the
site of infection -        ~ MMmmg&
Mast Cells: When activated/masfceHs rapid,l^^||p|^^i^|s^^^e^rich in histamine and heparin, along with various hormonal ~>~tt~*-~~ —A '•■■►"i—""      »•*.——---."»^^^Ji»*»*58ii»^^essels, causing the characteristic signs of inflammation, and
Oendrtticcells; these are phagocytic *»'il]^S^|^|ssU^t^^ire in contact with the external environment, mainly the skin, and the
nner.mucosal lining of the nose|Jungs;-|fehfa,cl^^iB^|^jfey are named for their resemblance to neuronal dendrites, but dendritic :ells ajre^notconnectedto the nervous,system, DeMr|tic*£ejTs^fe very important in the process of antigen presentation, and serve as a link between thejnnate andadaptive'immuhe systems.   'SSsff .
natural Killer Cells: They play a major .role jn the rejection of tumors and cells infected by viruses. The cells kill by releasing small :ytopfasm|c granules of proteins called |erVo|jn and granzyme that cause the target cell to die by apoptosis.   grtffl^srjuoba&e.
Clone Selection Theory. Rearrangement of immunoglnhni
m genes.
Variable Region: ; ..
Each person has the ability to produce a range of.indivldua! antibodies capable of binding a total of well over 10, epitopes
Chromosomal Rearrangement: each antibody has a unique gene encoding ,t, and a single germllne immunoglobulin^ undergoes multiple mutations that generate immunoglobulin diversity. £
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Primary and Secondary organs of the immune system
A number of morphologically and functionally diverse organs and tfssues have various functionsm the development of Immune system:; These can be divided into primary and secondary organs of the immune system. The pnmary organs are the thymus and bonemarrow, . which Is where maturation of lymphocytes takes place. The lymph nodes, spleen and various mucosal associated lymphoid tissues (MALT) make up the secondary organs, which trap antigens and provide sites for mature lymphocytes to react with an antigen
Thymus: site of T-lymphocyte maturation and development, situated in the anterior mediastinum. Divided into lobules; ea'ch'lobule has an outer cortex and an Inner medulla. Cortex is densely packed with immature TrceHs (thymocytes). The inner medulla Isisparcety packed with thymocytes. ^ 3e?< LJ.f ^ITJA5? -
Bone marrow: site of B-celi origin and development. The site of generation of alPcirculatmg blood cells -
Lymphatic System: as blood circulates under pressure, Its fluid component (plaTnia) seepsjthrough the capillariesintothe surrounding tissue. Much of this fluid, called interstitial fluid, returns to the blood through'tliecaplllarymembranes.:The.rema,indir:pfthi interstitial fluid (now called lymph) enters lymphatic capillaries and vessels, The largest lymph"-vessel emptiesjntottf^thoraclc duct, and re-joins the blr~d. Thus, the lymphatic system acts as a means for transporting lymphocytes andantlgens from the connective tissues to organised iyr,,(,nold tissue where lymphocytes may interact with the antigen and undergo activatioru      - -4
Lymphoid tissue is arranged into follicles. Until It is activated by^p'antigenp:a lyrrfphoid follicle is called a primary follicle (comprising of follicular dendritic cells and resting B-cells). After antigenic challenge; it becomeslarger andt?called "^secondary follicle.
Lymph Nodes: small nodular, encapsulated aggregates oflymphocyte-rich.tissue;: situated along lymphatic channels throughout the body, where adaptive immune responses are mounted to. ahtigens in:lymph.A*;lymph'travels through a node; any antigen that is brought with it becomes trapped In the cellular network   \ (Uuj^ (${^£0IA<tt$£ 0-f(ft£pi t? ^[u^i* CvAtfaJ^X
Spleen: a peripheral lymphoid organ located in the leffiupper, quadrant of the abdomen.'lt Is the major site for adaptive immune responses to blood-borne antigens. The red pulp ofthe:$pleen is composed of blood-filled vascufarslhusolds lined by phagocytes that ingest opsonlsed microbes and damaged redJ>!ood cells.y The white pufp containslymphocytes and lymphoid follicles. This is where the immune
reactions take place. 4^6.^ ^      *       -vtf-*^" 5?^
Circulation of lymphocytes in the body ??? ^        _ ^^^J,. fc^
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B-lvmphocvtes. production of antibodies, isotype switching.
B-iymphocytes are the only cell types capable of producing antibody molecules, and therefore they are the central cellular component of-' humoral immune response. B-cells express membrane forms of antibodies that serve as thereceptors that recognise antigens and initiate* the process of activation of the cells. Soluble antigens and antigens on the surface of microbes may bind to these B-lymphocyte receptors* and elicit the humoral immune response. j.^  j.j. ~~ ~
The effector function of B-lymphocytes is the neutralisation of microbe,fihagocytosls and complement'actlvatlon-^'"."'-.'.^'--".-
Activation and differentiation of B-lvmphocvtes; ' , t^f^>Wi^f '^4*1^
1) Antigen recognisiton - Ig In contact with microbe       \^ ^f* ! 3*^ 'if* -
2) Activation of B-lymphocyte - stimulated by Th cells, leading to clonal expansic^of activated B cejls ^
3) Differentiation - effector ceils are antibody secreting cells, class switching occuTs and'pfasma cell > memory B cell'
Stem Cell > Pre B-Celi > Immature B-Cell > Mature B-Cell > Activated B Cell > Plasma Cell> Memory B Cell }
Constant Region:
Different Ig classes or isotypes are determined by their 4xftaTnsSfecterlltics 2*      ^ > fy^S**^
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IgM: the first immunoglobulin of the Immune response%"entfmfefjTbThdsB:%pitopes}
Isotvoeswitching: 4*-^ ftfi     J| .
B cells have the ability to change the class or isotype of the^mmunoglobuliruthey produce. Itenables humoral immune response to different microbes to adapt In order to optimally coml?at:tfese'micj;obes ^antlbodiesnhat bind to the same epitope are able to trigger a variety of different types of immune responses  2L     ^ ,t ,
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T-lvmphocvtes, Th-cell subsests, their effector function
T-lymphocytes arise from stem cells which reside in the bone marrow. Immature lymphocytes migrate to the thymus. Thymocytes learn to: distinguish self from non-self, the ones that cannot do this distinction are eliminated, andthe others enter the circulation asT-cellsTT-cellsli initiate and regulate the humoral Immune response. T-ceils are called effector ceils and are responsible for cell-mediated.lmmunfe-:'J^'«-^ responses. They are involved in hypersensitivity responses, transplantation immunity and cytotoxic responses.    ,    ~~ *~
Activation of T-lvmphocvtes: 4% ^-s, > *
T-lymphocytes can be stimulated only by complexes of antlgen-HLA antigen. Th.e HLA antigen fnust be the same as HLA^antigens'of the
person from whom the lymphocytes originate (phenomenon of HLA restriction ;
Thymic Education:
Positive selection: survival of cells reacting with low affinity with HLA anti
those cells that recognise the HLA antigen of the person survive. The non-re^Wihll^cells'die by neglect.' fA^&aJfl^ P®$$$( _ Negative selection: those Thymocytes that react with high affinity with complexes p6Hl)A antlgensl!n the thymus ate byapoptosis
90-95% of Thymocytes die by this process. (l^J^\do'itA^C-^0<^
Immature cells that display both CD4 and CDS receptors are:tjallid^oUB|eS>6isitlve
recognise Class! MHO—'J------------------------------ -■-
recognise the Class II positive T-cells.
Activation and Differentiation
lis who
1} Antigen recognitlo 2) Activation: by Interleukins and E) Clonal expansion: proliferation
T-cells are either CD4 or CD8 but both'
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CD8: Cytotoxic T-lymphocytes - are actlvatldl^^^^^l^^^^ aro^^j^^^^^ells.
CD4: Helper T-lymphocytes - are activated by HlS^pjfitj'g!^ of macrophages (Thl) or B-cetts (Th2).     ~\ -
CD4: Regulatory T-lymphocytes^important of matntenaWiSfofcli Sou
tteJoTefance.
Helper lymphocytej^^^^^^^ JIS^
Regulatory lymphocytes
Thl cells:
5 k:v:
Stimulate phagocyte-mediated in|^^rL?^,gmp^oX^^^es.The most important cytokine produced by Thl cells is IFN-y which fs a potent activator of macrophageMtSiM^ of antibody isotypes that promote Phagocytosis of microbes, because
Stj^Bfete phagdcyte-jnjfe^ immunity which is especially effective against helminthic parasites. Th2 ceils
pr^|^^-4 whichii\^k^^tp0^^^of\%E antibodies. IgE activate mast ceils and bind to eosinophils. Th2 cells also produc|jL-5! ^jWcJj^Tvates eosinoph^So\me^|^ by Th2 ceils, such as IL-4, IL-10, and IL-13, inhibit macrophage activation and
sup^fls^TW-celUmediSted imh^n^i^^if(3fei^ieffideno/ of cell-mediated immune responses against a microbe may be determined by a:balance between the activation of ffif:a}Vd,Tfn2 cells in response to that microbe.
The development of TH1 and TH2'ceHsj.s hot a random process but is regulated by the stimuli that naive CD4+ T cells receive when they encounter microbial antigens (Fig. 5-i2). Macrophages and dendritic cells respond to many bacteria and viruses by producing a cytokine r^llpri [1-1 ?. Wtipn nslvp T r>!l<; rpr.n»ni7P thp anti?pn<; of fhp<;p micrnhps. whirh arp bp'me nrpspntpH hu thp samp APr<; the T rollc -^-^
exposed to 1L-12.1L-12 promotes the differentiation of the T cells into the Thl subset, which then produce IFN-y to activate macrophages to kiil the microbes. This sequence illustrates an Important principle that has been mentioned In earlier chapters, that the innate immune response— in this case, )L-12 production by APCs—influences the nature of the subsequent adaptive immune response, driving it toward Thl cells, if the infectious microbe does not elicit 1L-12 production by APCs. as may be the case with helminths, the T cells themselves *.'-.*. produce 1L-4, which induces the differentiation of these cells towards the Th2 subset. The balance between Thl and Th2 differentiation may be influenced by types of dendritic cells that initially respond to particular infections. Several subsets of dendritic cells have beenidentified that differ In the classes of microbes they respond to and the cytokines they secrete when activated by the microbes and. therefore, in the. types of effector T cells (Thl or Th2) that they induce. The differentiation of CD4+ helper T cells Into TH1 and TH2 subsets is an excellent' example of the specialization of adaptive immunity, illustrating how Immune responses to different types of microbes are designed to.be ■'■' most effective against these microbes. Furthermore, once Thl or Th2 cells develop from antigen-stimulated helper T cells, each subset wv.; \ produces cytokines that enhance the differentiation of T cells toward that subset and inhibits development of the reciprocal population. This "cross-regulation" may lead to increasing polarization of the response in one direction or the other
secrete the cytokines 1L-17 and il-22 and are the principal mediators of inflammation -
VST cells: ICt ^ >S   ,       ^ tbj <$f& V&V?S V&t U    ^ r
They represent a small subset of T cells that possess a distinct T cell receptor^TCR) ontheiTsurface. A majorjtypf T cells have a TCR composed of two glycoprotein chains called a- and Ji- TCR chains. In contrast.Tn y6 JacelisstheTCRis made Up'of oney-chain and one 5-chain. This group of T cells is usually much less common than aPT cells, but are fouMat.tfijir highest abundance in the gut mucosa, within a population of lymphocytes known as intraepithelial lymphocytes (lELs).  ^-1 (/^     ; ^
Comprise approximately 5% of peripheral lymphocytes, Theyyare;CD3*CD^-CD8- {double negative^-cel.sJiiThey have low antigenic specificity, and so are involved in the non-specific immune respotjse. Thethymus is not necessary-for their development. They are increased in mycobacterial infections, erlichiosis, and listeriosis   ->    ^    ^ ^ i
Intraepithelial Lymphocytes: -Z-t: ttfj 3
Are found in the epidermis of the skin and in mucosal epithelium (eig;:GITg-eproductive tract). Unlike other T cells, lELs do not need priming. Upon encountering antigens, they immediately release cytokines^and cause kljiing of.infected target cells. In the Gl tract, they are components of gut-associated lymphoid tissue (GALT) ^*  v      ^   ^    ^ 1 £"   ^     - '
lELs express gamma-delta heterodimer>4\4§£t gamma-delta ^ceH.receptor3:(TCRs) lacHhe CD4+ and CD8+ marker, but the gamma-delta TCRs of lELs are unique in that they ateCD8t) h *~
They function in the host defense bylecreting cytokines;:activating phagocytes and by killing infected cells.
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CD8+ cells, effector function.
CD8+ cells are also called Cytotoxic T-lymphocytes to reflect their function. CD8 molecules associate with TCR and recognise MHC ciass-l.'; peptide complexes. They recognise and kill host cells infected with viruses or microbes    o^o^OSfA-      -       ' ^
Naive, antigen specific CD8+ T-cells recognise MHC Class-I on the surface of APCs. Expression of CD80 or C086 by the^epti^e presenting' APC serves as possible co-stimulation as it engages the CD28 molecule on the CD8 cell f '"j
i~
Secretion of IL-2 and/or IFN-y by adjacent Thl cells may provide co-stimulation for the naive CD8 cell CD4 T-cells also produce cytokines that help to activate the CD8 cells.       A % -\ ' S ~^"3r    ^ ^
Cytotoxic T-lymphocytes adhere tightly to their target cells, mainly by use o^ifitegnnson their surface blndingjo hgands op thejnfected cejj^Tte^rrtig^n_ceceptors and co-receptors of the Cytotoxic T-lymphocytel.cTtfster?att^^ an ^nmunologic synapse^The Cytotoxic T-lymphocytes are activated by antigen recognjttpn*afid firnmdheslonj^this'sfagetSy do not recrair^^s^rrnttfatlctn for activation, therefore the differentiated Cytotoxic T-lymphocytesTare'able^o^ill'anyjnfected cell in any tissue.
Cytotoxic T-lymphocytes kill target cells as a result of,de1i^^;Wn3le^c^ins Into targetcells r: Granule Proteins ^     »   >   i   J    A   n    «     ^   i ^
^ ^{-t^fel *%gf:*£MSir!f
• Granzymes cleave and thereby activate enzyme^calledxaspases that arepresent in the cytoplasm of the target ceils, and the active caspases induce apoptosis    ^     "    J   <    ®, *-SL  ^*   -£>    £■ ^
• Perforin is necessary for delivery-of granzymes into cytoplasm >of target "cell::.
• Activated Cytotoxic T-lymphocytes alsoiexpress amembranepl-oteinicalledFasllgand which binds to a death inducing Fas receptor on target cells. Fas activated caspases:and induces targetcelt apoptosis. Cells that have undergone apoptosis are rapidly phagocytosed and eliminated ~\   *     s-      v  ^ C j^iS^0^ V
Natural Killers - NK cells (large granulated lymphocytes)
Large granulated lymphocytes which originate in non-T, non-B lymphocyte lineage. They do not require prior exposure to ah antigen- They provide immunity against virally infected cells and spontaneously arising tumours, thus acting in immune surveillance. Their target cells-are-characterised namely by decreased HLA Class-! expression (viruses inhibit class I MHC expression), and some target cells display an''     '■• :J activating ligand for NK cells, " v
NK cells, along with macrophages and several other cell types, express the FcR molecule, an activating biochemical receptor that binds the Fc portion of antibodies. This allows Natural Killer cells to target cells against which a humoral response has beenmobilized and to lyse cells through Antibody-dependent cellular cytotoxicity (ADCC). Their cytotoxic mechanisms are similar to Tc ceils: pjrforiii and induction of-, apoptosis, ^ =     ^"5^/** " ^   _ - ^r **
NK cells express complement receptors type-3 and type 4 (CR3 and CR4) that recpgrtise and bind to rpembrane'bound C3b: They do not ( express TCR or immunoglobulins. ^   5j    *■    *J ~*  \ ^§p«.3\M&£^\
NK cytotoxic activity is augmented In the presence of type 1-IFNS (a and b) which are produced by.vi'rally infected cells, and by cytokines such as 1L-12 produced by phagocytic cells. % »5 ^ ^ %#
A    \ited NK cells also secrete iFN-y to activate macrophages to.beconqe more effectiveiat kllltngphagocytised microbes.
Macrophages ingest microbe and produce IL-12 > lL-12 actTvatesTvjK-rails toltecrete. IFN-y > IFN-y activated macrophages
Dendritic cells and macrophages that have encountered. mferobes;abo%crete:cyi;ol<!ne IL-15 which isimportant for the development and maturation of NK cells.    . t i
NK cells have inhibitory receptors which recognise seifelassjUMHC^iolecules thatire.expressed by ail healthy nucleated cells, ensuring that NK cells do not attack normal host cdls.:«i& % ^^i^r^T SA.^ a* % 1-1l" *-
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Interferons
Virus
Kr- Viral nuclelo
prptems & A -epralüOügn
Interferons (IFNs) are proteins.made and released by the cells óf most vertebrates in response to the presence of pathogens — such ás viruses, bacteria or parasites — or tumor ceils They allow communication | between cells to trigger the protective defenses .of the immune system . that eradicate pathogens or tumors ™ *" 'i
IFNs belong to the large class of glycoproteins knówpíäs cytokines . Although .Jhey are named after their ability to,"interflre" with Viral replication within host ce|Js IFNs have other functions they activate immune _cells such as natural killer cells and macrophages they increase .  recognition of Infection or tumor.ceHsbyúp-régulatlng antigen^
presentation:tó;T;lymphQcytesílnc|^tey increase théľábrfítý of . uninfected hpst;cells. to resist new infection by«ytfus5JCértaín host symptoms such ás-achirirmuscles and fever art related f5 the production of IFNs during infection %   H *
ft Themajor^sources of IFM a aremačŕdphages and dendnticcells while * forJFN b are the fibroblasts '£ T&l v NVv cŕ J t s
í 5?   2  t"       ^ f
^IFN^ andJFN bTare secreted byjnfected cells and bound by receptors of ^eigbboujing.unípfected celis/lnjdoirjf soľ genes which code for antiviral ;;:aP,rptejn5,are;activated and the suBseqcTentantiviral proteins block viral reproduction #   ^ 3
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Host Coif 1
Infected, by vírusy mahés mterfcíroh,1 is killed by virus
Host Celt a
£j>tersä by Interferon frort! pelf iQrj^rftr&n ^ induces chärígesTfíat
JFN yjs a cytokine producecLby Thl lymphocytes and NK cells whose ^tin%al,f%ctlonjs tojactlvate.macrophages in both Innate immune ;}.resppnses:Md:adapti^.ce|l3iediated immune responses-
:•%?=•..'■,< '•^.i'-'.-.
JFN-a is used, clinically to treat chronic viral hepatitis.; £C»tfc>-
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immunoglobulins, structure, function. Isotypes, idiotypes.
Immunoglobulin is a generic term that refers to a diverse group of molecules found in the blood and tissue fluids. An antibody is an • - • Immunoglobulin molecule capable of combining specifically with a known substance (an antigen)
Immunoglobulins are synthesized by B-lymphocytes and by terminally differentiated plasma cells. They can act directly Upon the antigen to which they bind to render it harmless, or often they 'tag* the antigen for destruction and removal by some other component of the .-'iv: immune system.
s
Structure: , ..
4 polypeptides - 2 heavy chains, 2 light chains (glycoprotein chains linked by disulphjde bond)      ..
different types of heavy chains (delta, epsilon, gamma, muJc^ftV^     *>'j i^,1 2 types of light chain (kappa and lambda) 4'f-s^ > ^ *       -,s£* -<- ^ h'
%£r?^K -S3"5 *   , _
Both heavy and light chains can be divided into regions or domains, homologous portionsof an;immunoglobulin chain containing an intra domain disulphide bridge.
Light chains have variable and constant domains (Vl and Hl) They have 212 residues    "~ '-f
Hf-'vy chains have a variable domain and 3 constant domains (Vh. Ch1..Ck2. Ch3) ??? draw on diagram%they have 450 residues.
The amino acid sequence determines the conformational structure.of Vifand VcThe variable region is the antigen binding region of the
immunoglobulin molecule (paratope).
Antigen binding-site
binding site    *   \ P°rtlQn's foncomplement^binding ^
NHjV'the htnge.region !swherethea™s:of.thearjt[b~pdy molecule form a Y shape, this is vbecausWthereis some flexibility at this po'lnt%lf
1>K)W/ ..-The hypSrvanabte region of the immunoglobulin molecule binds the epitope, chain ~*    ^ -*
Disulfide bonds
:COOH
Cleavage of Ig molecule bv proteolytic enzymes:
Immunoglobulin moleculesjcan be:enzymatically cleaved into discrete fragments Hinge reoion eithej. bypepslon or papalm-Disulphide bonds join the heavy chains at or near a flexible proline^ich hinge resion, which confers flexibility on the Ig molecule.
Fragments of Ir:w;•■ •■■f.--,-,
The Fab or antigen binding fragment is produced by cleavage of papain. ??? it aconsists of VhrCjilSVf arid CI.
:;.The Ec or constant fragment is produced by cleavage of papain. Contains Ch2, Ch3 Mand sometimes Ch4. It is responsible for biological activities that occur following :f*s:engagemenlof,antigen"by antibody, including activation of the complement.
Heavy chain
isotype _ ' ~
This is the subclass of an Ig. It Is determined by which of.the different forms of Ch are present. The classes are IgG, IgA, IgM, igD, and IgE. tach isotype-hasa distinct physicafand bioiogTcal properties and effector functions.
Idlotvoe * r    ~l. ~-
An antigenic determinant.on the;vanable region of a specific antibody, located on the Fab fragment. Antt-idiotvoic Antibodies: v'.
Antibodies which are elicited to the Idiotypes of other antibodies are called antiOidiotypic antibodies. They are directed against the hypervanable regions of an antibody and prevents the antibody from functioning. They are important in autoimmune regulation.
??? look in notes for importance
The basic chain structure of immunoglobulins
The basic structure of IgGI
^variable tegion
heavy chain (450 residues}
antigen binding sites
sir
The strength with which one antigen-binding surface of an antibody binds to one epitope of anantigen is called the affinity of* the interaction. Affinity is often expressed as the dissociation constant (Kj). which is^the molarconcentratloi^of anantigen required to occupy half the available antibody molecules in a solution: the lower the Kj. the higher the affinity::/-.v.5fffife'.'
1
Avidity is a measure of the overall strength of binding of anantigen witfJ;m3nyantigonlcTdetermin3nts and multivalent antibodies. Avidity is influenced by both the valence of the antibody and thevalence?of the^antigenFAvidlty is more than th'&sum of the individual affinities. t> CX>\\ZC&a\^J&)   erf twJJU^ViV^^^ Jj^  0~f[    3§&W^Lm} ^      C > Aß.
IgA:
» Monomer
• major immunoglobuliqjcf serum        s-5    \ >■ r?
• exist as : IgGI, lgG2,igG3 igG4 -J"^ > ^ AF_
• IgG is the major antibody of secondary response and, is found in both serum and tissue 1 - it is the only antibody that is capable of crossingthe placenta andgiving7passive immunltyto fetus -Ti if   I ^ t»
fluid. fcRSp«"fc
'-.■Jag» *
- v.
•Dimmer   Ot^V 0 ^ '^RkSw^t *Jbfc*vjC*l>
• Found.in breastmllk,:rmicosal areas, respiratory tract,' urogenital tract,
IgM:
• Subclasses: |gAl;lgA2
• Large size hence confined to Intravascular pool   ^,£0^' p\?VW ^       </A^^ (W 3 ö| £i£,utM/A^-  * First an.ti.body3ype,to.he produced dwing^imrhuneiesponse jdq,       IgB IgD
IgD
igEr >
^^-.•Monomer   _ 'wx
j-- • Many .circulating Bcells have IgD.present on/their surface.
•Monomer
• Present, irvvery low. levels .•
• Found on the.surface of mast cells and basophiles.
• Triggers histamme.release from mast cells and basophiles, involve in allergy,
Monoclonal antibodies. Production, properties, therapeutic and diagnostic use. +\i liM^$fi4^M^k^^$=/H:
A monoclonal antibody is an antibody that is specific for one antigen and is produced by a 8-cell hybridoma (a cell line derived from the fus.on of a normal B cell and an immortal B-cell tumour line). They are widely employed in research and clinical diagnosis and therapy.
They are prepared by immortalisation of 8-cells from an immunized mouse. Hybridoma is composed of an antigen-specific B-cell and a mouse myeloma cell.
©isolate SfttenalU fa<« wol^.^m^     -       y0„i\W>M ***** w°/
l.O J^1    ^ -----■ , "
,,,,      — ^
© JUtfcWw. ^stuaw) "kno«o<:U»vai. feu << J
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, 1_ vi-„\Woar SbtouV- wc.Mjc-tc™.t, o.Vo cv* u*iA ix> Ai&ct ^wai«    <ifa*j^s«c
Reaction of antigen and antibody in vivo. Consequences of the reaction in vivo.
Affinity: the strength of the binding between a single site of an antibody and a single epitope. It is the sum of the combining forces between the antibody and the epitope. The higher the affinity, the more stable the interaction.
Avidity: the overall strength of the Interaction between an antibody and an antigen. The avidity depends on; the affinity and valency of the interactions, which is more representative of a real situation. ^(.fcwJtijut e| ymlL-UrXt V*a&m^ oa a>°
The ratio between the antigen and the antibody influences the detection of Ag/Ab complexes, because the sizes of the complexes are related to the concentration of the antigen and the antibody.
No covalent bonds are involved between antibody and epitope.
Binding forces are relatively weak: - van der waais forces
prostatic forces i * \?A.
-hydrophobic forces
Can be dissociated by: low or high pH, high salt concentration
Biological functions of Immunoglobulin molecules:
Activation of complement system (IgG, IgM) i^'ToHA^
Opsonization (particularly IgG} /" '
Neutralisation of antigens (IgG, IgA, IgM)
Antibody dependant cellular cytoxicity (fifocc*)
Agglutination and precipitation (IgG, IgMJ
Mast cells degranulation (IgE)
Transport through placenta (IgGj^rU^/WU-'* tVe--.
Immunoregulation (IgG) -cm^ ~ ;;; V:MMW,\
Antibody-dependant cell-mediated cytotoxicity:
Antibodies often recognise and bind to cell-surface antigens, such as those on parasitic pathogens. Eosinophils and NK cells recognise alterations in the Fc portions of the antibody, and kill the antibody decorated cell. NK cells have a specific Fc fragment receptor called
Agglutination Is the reaction between antiserum and corpuscular antigens (erythrocyte, bacterium, latex corpuscle). The corpuscles are clumped together, which morphologically expressed as agglutinate (Direct agglutination is when the Ag Is a natural constituent of a particle, passive agglutination is when the Ag Is bound to a carrier particle e.g. Latex).
Precipitation is the reaction between polyclonal antiserum and soluble (molecular) antigen. A complex lattice of interlocking aggregates is formed. If performed in a solution the precipitate falls out of the solution.
Titre: the agglutination of antigens as a result of cross linking by antibodies is dependant on the correct proportion of antigens to antibodies. There is no agglutination at higher dilutions because there are not enough antibodies to cause visible agglutination. The highest dilution of serum that can still cause agglutination, but beyond which no agglutination occurs is termed the titre.
CQombsTest: Ceo?v^ vto^AU ftfa *aV>Vxt arfo-Ww**
Employs antibodies to immunoglobulins = anti-immunoglobulins. 0 q,     >^ ^
1) DIRECT - anti-lmmunogiobulins added to particles (RBC) when suspected of having antibodies bound to antigens on their surface, it measures the antibodies. E.g. Baby with anti Rh-lg antibody on RBC.(W|('4ik$f}.ot\
2) INDIRECT - detect in the presence in serum of antibody specific antigens on particles. It measures the serum antibodies. E.g. Anti Rh-lg antibody in the blood of an Rh- woman.
Mucosal Immunity
<- J J ' '/V\ ^ COS oS :: 5 £ ia<?.<L ,
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Specialized epithelial celts in the salivary and lacrimal glands, respiratory tract, small intestine and breast tissue bind dimerlc IgAat their internal surfaces using a specialized receptorf^sjgAywhich is prevelant in mucosa. Dimeric IgA is then transported through the cell and released on the external surface. A portion orthe receptor remains with the secreted IgA molecule. The receptor remnant, known as the secretory component, gives the secretory IgA additional protection agasint degredation in the exterior environment.
The mucosal immune system is a part of the immune system that responds and protects against microbes that enter the body through mucosal surfaces such as the gastrointestinal and respiratory tract. The mucosal immune system is composed of collections of lymphocytes and antigen-presenting cells in the epithelia and lamina propria of mucosal surfaces. The mucosal Immune system includes intraepithelial lymphocytes (mainly T-cells) and organised collections of lymphocytes (often rich in B-cells) below mucosal epithelia, such as Peyer's ;:; patchesjn the guts or tonsils in the pharynx.
Antigens enter the gastrointestinal tract, and lodge In the MALT. There, they interact with macrophages and lymphocytes, Antibodies are synthesized and deposited into the local tissue. Also, lymphocytes entering the efferent lymphatics are carried through the efferent lymphatics are carried though the thoracic duct to the circulation and are distributed to various tissues,
MA IT (Mucous Associated Lymphoid Tissue): % a. ^ ^ '    * J N
6   )-gut associated lymphoid tissue 4    ^ '' \ u fc^/f^H
BALT-bronchi associated lymphoid tissue   ^J.^-^^ ~Z) W*^-* lr^ (J^L*
Immune tissues of the urinaty tract, genital tract, conjunctiva, breastglands, etc.
Diffuse tissue containing lymphocytes and other cells of the immune system in the sabmucosa. Specialized organs include: Waldeyer's ring (tonsils)
Peyer's Patches (10-200 nodules, mainly B-cells, covered by M cells) Appendix
Antigenic stimulation In one part ofthe MALTieads to immune responses in other compartments of the MALT, IgA isa predominant immunoglobulin secreted through the epithelial cells. Oral administration of antigens usually leads to induction of immune tolerance.
Peyer's Patches > Mesenteric Lymph node > Thoracic Duct > Vena Cava
Homing of lymphocytes = Migration   ; /p -*rr oiv
This is the directed migration of subsets of circulating lymphocytes into particular tissue sites. It is regulated by selective expression of adhesion molecules called homing receptors on lymphocytes, which signal to the lymphocyte to migrate. Tissue speciphic endothelial ligands are called addressins.
Hu...-endothelial Venules: ^
These are specialised venules, which are the site where lymphocytes leave the blood stream and migrate into lymph nodes, spleen, and other organs ofthe MALT.
Intraepithelial T-lvmahocvtes: hi .if) tlr^l
Located between endothelial cells/enterocytes. They have a TCR composed of either aB or yd. They undergo thymic differentiation, and are the first line ofthe specific immune response. They are predominantly CD8+, and their TCR has low antigenic specificity so can react with many antigens.
M-cells:    HwJoU qMa cyttoyt, §Oto& pexUW>
Specialised enterocytes responsible.for the transport of antigens from the gut towards the immunocompetent cells inside Peyer's patches. They can Ingest material at thelumen surface and transport it through the cytoplasm to the basal surface where underlying lymphoid tissue is located.Transportis mediated by transcytosis ^ the transport of macromolecules across the interior of a cell,
J kiU H-Hr Mjiytm       |pL fu^i p^(Lt/i
Regulation of the immune system. Th, Treg cells, Idiotype- -antiidiotype network _:
Some types of regulatory lymphocytes block the activation or effector functions of potentialJy;harmfullypiphocyteswhicli;are specific fori self antigens. Failure of such regulation may result in autoimmune diseases *"" j-
Negative selection in the thymus is also a way of refulation of the immune system, as T and B cells"wtth'potemtta! reactivity to self molecules are deleted. ^fOp^LV. 5^ VUjL qv^> $auL tue!   -toö s^ßij h  HHciö&f      ' ^ ^5
Supresslon of immune response: /is.        '~     '<        ^        ^ 1* *** ~l
Certain T-cells can suppress antibody production. There is evidence that insome situation's, CD8+ celts can suppresspbutvinhibitoryr lymphognes produced by CD4 cells are also important. " (xy rc% -    * äs
TregLymphocytes:                                           . \=f   fcy=*  .     *'   , ' Jf ;p~-
Subset of CD4+ cells (5-10% of peripheral CD4 cells) ^   ^ U|i C4$jK 1L 4"T^_fUxkxe<UL<t,
Ge^Rrated by self antigen recognition in the thymus * J j     I      * ,  < t
Sl   )sf*^ctfon against self-antigens by secreting IL-1Q ^j^Rj        f ^ (L-10 inhibits function of macrophages and dendritic cells
Generation and survival are dependent on cytokines TGF-ß and_IL2      ^ { Q{j M^.^jjJi L^[0        w<*.cs& *
TrI cells:-f&J *   a* .3*1   -f C-S^' ^ ' '   ' #    "! •VUCtJ'
Antigen-Induced regulatory CD4+cells tL!    Jf"? -
Develop from antigen stimulated T lymphocytes in.^lOJenviro^m'ent/tolerat&'foreigniAg's Produce IL-10 and IFN-y and TGF-B ^k*       rc jv-"' ;y    - -j*
Can cause inhibition of T-cell activation ^ 1. '^^f^^^^^     ^    I "7 >
Th3 cells have a similar function ' _7        C        * "T^ !flr ^ "f
Benefits:_■_Harmful:       ~ ~ ' >-
T-cell homeostasis rf-   Down regulation of tumor immunity ^
Prevents autoimmune disease Downf egulatton of immunity to infections
Tolerance after transplantation Prevents allergy
Prevents hypersensitivity    >f£%íi - ^
Cviv,Jnes: .^lu1^.     J,(<jjj&^{ ^^-w^t. Aly^t
Usually affect-many cell;ljneages,;with.both stimulatory and inhibitory effects ř /
Can have pleotropic effects       v_ - . j1 ,  t., !aJ\/C Ci^''Q
Effects of cytokines: ^ '        ^ C Mi?,a^.. V...,-?...........1^        '        f \~\* 'li     r^hx/^ukM I
• Pro-inflammatorycytokines'IL-l-;lL-6,TNF-af,ř ^ jLJ^\\<>fi t-M-^Y
• Stimulation of macrophages: tFN-g      ,, ^
• Stimulation of granulocytes lL-8_ *>
• T-lymphocytes stimulation IL 2 - -ti ^'
• -   B-lymphocytes stimulation, production of antibodies: IL-4,1L-5, IL-6 í 1-
Negative regulators: 1L-10, IL-13,li,F^ ^ \ — 0
Mutual inhibition ofThl ancÍTh2 cells "
Thl produces IFNy that inhibits maturation of Th2icells, and TNFp that leads to supression of T and B lymphocytes. Th2 produces 1L4 (increases Th2) and IL10 (inhibits maturation of Thl cells).
Idiotvpe-antildlotvpe network:
Idiotypes are antigenic determinants on the hypervariable region present on Ab's or on antigen-specific receptors on T and B cells. Every Idiotype can be considered a self-antigen for which a complementary anti-id could be formed. Anti-Id is an Ab that treats another Ab as an Ag and supreses its immune activity. z      ^ - *
Anti-Id Antibodies that recognise and regulate the expression of Id on the cell surface play a role in self tolerance and prevention of _ autoimmunity. This network also exists at the lymphocyte receptor level where idiotypes occur like in Ab's Negative Regulation failure can lead to autoimmune diseases. ^      * Z' i
Mechanism: Activation of B cell results in a clone of plasma cells producing Ig of a single idiotype which%ecausett was;previousIy present in very small quantities can be recognised as "non-self and result in the production of anti-idiotypes Ab's directed against its idiotypic. determinants. These Ab's react with Ag receptores on B or T helper or Supressor cells as'well as circulatory Ab's to enhance orsupress-production of the initial Ab by various mechanisms = ' ^"
e5
4   ,   iID 1 *T\
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Immunity to viruses. Mechanisms of the host defence
Immunopathological consequences of the reactions against : invading organism. ? ^ 3
Factors Influencing extent and severity of infection: " ~" t---?
Pathogen factors-Dose, Virulence of organism and route of entry * -
Host factors: Integrity of non specific defenses, competence of the immune system, genetic influences; previous exposureaoantigen and existence of co-infection. ^*
^%* , " 5 - ^    ~    v ,
Virus are obligate {must provoke disease In order to survive and be transmitted) latracejjular pathogens!a"rYdruse host'CeiLreplicationV machinery because their genomes are too small to encode this machineryWThey. often kilhmfectedcellsiand spread to adjacent cells-to repeat process. Virus replicate in cytoplasm so viral products are availableibr^roteasome^egrad —"~n
complexes. B cells generate humoral responses to viral epitopes but the Ab"'s generatodrcannot clear-virus^because they gresequestered] within the cells, but Ab's can prevent a possible re-inlection. Ab's can neutralize and opsomse virus. ^ '3 />i /
Mechanisms of host defence against viruses: »^ Hi    >ecificImmunity: }\$A-QpU(fic> ^Jtj?"  ^ ~
1) Interferons (main one) - Type I 1FN (a from leukocytes, (3 fromfibrobtists, both m crease expressiojfgfMHC I for cytotoxic T-cells ) inhibit the intracellular replication of viruses. ^II^~       , ^ IP'
2) NK cells - like cytotoxic T-cells, secretes perforin causing1 apoptosis -££0> ^cJl ^t>< ^AtXX s*
3) Activation of complement.   AUuMtf*<-       j\^%£~L* ~x * "ft^1       ' i
4} Phagocytosis (phagocytes become activated by binding of PAMPS of viral cells to PRR and secrete cytokines that trigger release of Acute
Phase Proteins from liver and induce fever).      /Ip^-1 Tr^"    ^Sl""       1 v
5) Receptor tike substances on mucus. /"J3§        **I ' ^     *, -     -3V '2?
Specific immunity; ^V'sfir        % "
1) Ab's - neutralisation by binding to virusand blocking thermfrom host^eri«ntry/.usuallyilg(3:'and-.lgAjf;-
2) Cytotoxic T cells-elimination of virus infected cells i \))^"*j:?^\tCC'
/ -50
Viral strategies to evade immune response timmunosuoressive effects)
1) Antigenic drift: accumulation of smallirnutationsithat alterifepttopes ommfectious agents;
2) Antigenic shift: recombination creates major changes in theiantigenicdeterminantsrof.the virus, happens when 2 virus infect the same cell and recombine, *l
Long term survival, ^ ^ H> z ^(rc^
3) Vi"l persjstance - integrationof a DNA provirus into host cell DNA (Herpes virus)
4) .    lunosuppressive effect^ a) suppression of T cells (HIV, morbilll), b)d*ecrease expression of MHCjnoiecules ex:CvM binds to B2-microglobulin, Adenovirus>'<RSV>decrease^te expression of HLA antigens, c)production of inhibitory cytokines (EBV).
5) Viral Latency-incubation (Bepres virus) ^ \L~\o ^> \ *XA>!k vw&Avt)"*'.
6) Oncogenic tronformationT Human T cell Leukemia virus i       _ d-itv-jsUJr-^
Damage of Host cell bv antiviral immune response^"^ O-W^^'^^ CAr¥^ ^ f .      ^jj  ()Ae/j^ iplU)^
1) Autoimmune diseases.{=he_rnolyticanaemia afteri€BV infection; autoimmune hepatitis from Hep BT}   ^  ~J   \ ,
2) Immune Complex diseaserarthntislri~Hep B, SiL*
3) Tc mediated diseases: rash In exanthematic viral diseasesymyocarditis caused by coxackie virus.
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Immunity to bacteria. Mechanisms ofthe host defence. Immunopathological consequences ofthe reactions against invading organism. ,     :i 1 v - \
Non-specific Immunity:                                                                                  ~ ■ - ^ - _\
- mechanical barriers                                                                                      " — *Z s= ^
- Phagocytosis ~    1/ '   "  * v
- complement system                                                                    + _~   S     ^ < Specific Immunity:                                                           ^' jr   *-??-'        c r               ^^f^^r3" ^
- antibodies (opsonisation, complement activation, neutralisation of toxins, binding to receptors) 't-          :| ] yv\0^<*
- T-lymphocytes (against intracellular parages, e.g. mycobacteria can stay inside macrophages, macrophages present to Thl cells that produce NO to kill them) -JL~       ^t" ""1"*
Bacterial Evasions of immune defences: <*rT- ^   ^ ,5V   - ~~
1) )(,!j%^iagocytic mechanisms (polysaccharide capsule) and also " 3, '
(j) inhibit Chemotaxis. Staphylococcus Aureus, produce toxins which inhibit the movement of phagocytes, which hinders them In their journey. ^    -r' ^4*%       1      ^  ^   <-t =r
fa inhibiting Phagocytosis. Some bacteria evade Phagocytosis by not presenting any signaWor phigocytes to grip onto.
By killing the Phagocyte- releasing toxins that are lethal to th£ Ph'agocytes^o instead of the invading bacteria being destroyed, ^ the defending phagocytes are.themselvesgestroyedi:{IVIycobaeterium;tuberculosis, Streptococcuspyogenes, Staphylococci, and BacillusAnthracis) tJZ _Z JSr   "^r  -* ~*
ft\By colonising the Phagocyte, the invadihgtbacteriaiallows Itselfjtobe Phagocytosed,<but reslsting^belng killed once they are within v'the Phagocyte. Many types of bacteria usj} Macrophages as srtes;of sanctify; where theycan-multiply without interference from
other cells ofthe immune system;:As mehtionedabove; bacteria that use;this strategy include Mycobacterium leprae and
Mycobacterium tuberculosis „■£*       "VN        - - -        , *
^ A
2) inhibition of Complement system (Str* Pyogenes, E coli n meningitidis),
3) Antigenic variations or drift-(borre!ia"recurrentrs),       *" ~~ * "■<.
*    ,Z............ -
4) Proteases lysing IgA (neisseria, haemophlllus), _' -
5) Inhibition
n of phagosome lysosome fusion (Mycobacteria)^t'Oc<H^jjii^S(/^v( f fivf ation in avascularregions (salmonella typhi in thegallblader-and Utract);
7) Intracellular parasitism      „ 1 ^ _ —*~
Bystander damage caused bv the immune responses bacterial infection:?? ■ *
Immunopathologwai copsequencesofth Autoimmune diseases:
- Cross reactivity of.ba_cterialand;CorporaSntigenspJ^reptococGUS Pyogenes > circulating antibodys affect similar cardiac Ag)
- Type II hypersensitivity.(autoimmune hemojytic:anaemi3ca:used by Mycoplasm infectionjf^?' ^   .   A|£p yy;f<
- Immunocomplex diseases (deposition ofjmmmunocomplexes in tissues) MfG fvtU     fUJEwtt^^C ^C J -Type IV hypersensitivity (cavitation in pulmonary,iTB-and Grave's disease) 1  ^ ~~~ CQW-WML&k
^ 0/0. >M'JtyKf-/^u&&«j
Vaccines, Vaccination.
Vaccination is an inoculation of a non-virulent or inactivated microbe as a means of inducing specific immunity/
Characteristics:
The vaccine must provide effective protection against the pathogen, from which it is derived without significant danger of causing the disease or side effects. The protection provided by the vaccine must be effective over a long period of time.The vaccine must stimulate : development of those immune responses that are most effective against the pathogen in question. '      '- "-
Classical Vaccines: i^X ^\ a ^wo%t*,b*t ifcU Wp^a       v]a.kk W) *
Attenuated live vaccines - When the inactivation procedure to make an inactivated vaccine destroys or modifies the protective antigenicity
(immunogenicty) of the organisms, the solution is to use suspensions of living organisms that are reduced in their virulence(attenuated) ,
but still immunogenic. Mumps, Measles and Rubella vaccines (combined), the Varicella vaccine andlhe'Cholera.,.vacclne:^tr.ft);.'.vii{'ir'. /   ' '
SOT ^ * '
Inactivated vaccines - If the disease is not mediated by a single toxin, it may bepossibie;to stimutatethe production;of protective antibodies by using killed (inactivated organisms) this is done in vaccines against Pertussis (whooping cough);influenza.and.inaetivated Polio (Salk)vaccine.        rjo-AeUo uMcV cua opj.fi. \* o.iUti,»s.,<        v.idU^Wo- 'mtl'&d '&vr!Aa<^ V^t *k .|&tvwaVV'i.j,j
Tc.   ifs-when the signs and symptoms of a disease can be attributed essentially to the effects of a single toxin, a modified form of toxin, that preserves his antigenicity but has lost his toxicity, like in case of tetanus and diphtheria.-
Attenuated Microbes: MMR, Varicella, Cholera j^Jrju^X-* ic&'yo*^ t\a),iAyVwo inactivated Microbes: Hep A, Rabies, tick-born encephaliUs^cJio^oLlkyactArtt) ' ■
Toxoids: Tetanus, Diptheria (should not be given to babies before one year because they might be immune deficient)
„Modern" vaccines
'jutu*. 4^ff^i
• Subunit: influenza, pertussis
• Polysaccharide: Heamophilus influenzae B£conjugated), Meningococcus (group A a
i^C, conjugated on non-conjugated), Pneumococcus (conjugate and non-) conjugated)
• Recombinant: hepatitis B
„Future (?)" vaccines
• Synthetic polypeptides
• Antiidiotype antibodies-ho |>ft^*g'^e
• DNA vaccines f
• Vector vaccines
• Antigens inserted into food (bananas, potatoes)
Passive Immunizations
Passive immunization.is where pre-syntheslzedclements ofthe immunesystem are transferred to a person so that the body does not need to produce these elements-itself. Antibodies are.used in this kind^ofimmunization begins to. work very quickly, but it is short lasting, because the antibodies are naturallybrokendown;and if there are no B cells to produce more antibodies, they will disappear. Passive immunization.occurs physiologically.in pregnancy.in.transfer.:ofcantibodies from mother to fetus Artificial passive immunization is used in clinical practiceiwhen it's necessary to protect a patient at a short notice and for a limited period. Antibodies, which may be. antitoxic, antibacterial or.antivirali in preparations of human (homologous) or animal (heterologous) serum are injected to give temporary protection;.Homologous antisera are much less likely to produce adverse reactions, and their protection last longer (3-6 months) against heterologous (few weeks). • i   :   ,: •
Treatment of diphtheriais made with antiserum raised in horse against diphtheria toxin (equine diphtheria antitoxin), also a similar serum is used in botulism, and stilf some'eountriesusedequine tetanus antitoxin,that is being replaced by human tetanus immunoglobulin. Active immunization entails the introduction of a foreign molecule into the body, which causes the body itself to generate immunity against the target; This immunity comes from the T cells and the B cells with their antibodies.
Active immunization
Active immunization can occur naturally when a person comes in contact with, for example, a microbe. If the person has not yet come into contact with the microbe and has no premade antibodies for defense {like in passive immunization), the person becomes immunized. The immune system will eventually create antibodies and other defenses against the microbe. The next time, the immune response against this: microbe can be very efficient; this is the case in many of the childhood infections that a person only contracts once, but then is   : . -
immune. Artificial active immunization is where the microbe, or parts of it, are Injecte&intathe person before they areable to take it in* *-s naturally. If whole microbes are used, they are pretreated, attenuated vaccine. Depending on the type of disease; this technique also works with dead microbes, parts of the microbe, or treated toxins from the microbe.
Active and passive immunisation
Spew) of response
Active Imiaufllaadofl
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Passive Immunisation. Immunoglobulin Derivates:
Passive immunization is where pre-synthesized elements of the immune system (anljfaodies_or lymphocytes [lymphocytes must be transferred between histocompatible individuals]) are transferred to a person so that the body does not need to produce these elements itself. Antibodies are used in this kind of immunization begins to work very quickly, but it is short lasting, because the antibodies are naturally broken down, and if there are no B cells to produce more antibodies, they will disappear. Passive immunization occurs . physiologically in pregnancy in transfer of antibodies from mother to foetus. ' '
Artificial passive immunization is used in clinical practice when it's necessary to protect a patient at a short notice and for a limited period. Antibodies, which may be antitoxic, antibacterial or antiviral, in preparations of human (homologous) or animal (heterologous) serum are injected to give temporary protection. Homologous antisera are much loss likely'to.produce adverse reactions and their protection last .v longer (3-6 months) against heterologous (few weeks). _   '' / .       ■ ' '
Treatment of diphtheria is made with antiserum raised in horse against diphtheria toxin (equine diphthería;antítoxin)/íá1so arssmilar serum is used in botulism, and still some countries used equine tetanus antitoxin thatis being replaced býhúmantetanus immunoglobulin.
-substitution of missing specific antibodies -us^d mainly against toxins ■p.  ]ffi$k short term effects
-no immunological memory is induced _._     - \ . _-_ „s
Pooled Igs are prepared: first collection plasma or serum fer healthy (immunizbd):donor, then p'rectpitationwith coid-ethanol in order to increase the proportion of Igs concentration: This precipitationleadstotheseparation of gammaglobulin fraction from total human serum. Final preparation should be free of hepatitis and HlV.virus." ;
Immunoglobulin Derlvates: •        -   \' \ - \
- normal immunoglobulins (forintramuscular.use,used rarelybecause dnly.a low.dose can be givenf»%é«w A i* j*m*]h-I {Vr i ✓»<••,«:.• o )
- intravenous or subcutaneous immunoglobulins (can be ušed in higher doses) •
IV immunoglobulins are special preparations which are treated to reduceiaggregation of globulins, lowering the possibility to develop anaphylactic reactions. ~.    ~       . ■■
Indications: "   " -> *
-replacement in antibody deficiency " -j\ojSéMť^^\-At
-prophylaxis of infections against which there is no specific immunoglobulin deriváte (Hepatitis A) V
- High doses of i.v. immunoglobulins are used in autoimmune diseases;;systemic vasculitic diseases, (in idiopathic thrombocytopenia p^ipurt> 's$, after splenectomy, intravenous Ig blocks Fc receptors on phagocytic cells and prevents them from destryingthe antibody coated iets } - '
plb.Jet:
in people with IgA deficiency>;they are not used to IgA in their bodieSi so.after a transfer there can be an anaplylactic shock by production of anti-lgA.,
ptuation for use of Antise'raf
- Against bacterial infections: Tetanus (human derivativerTIg: antitoxin administered after some wounds), Diphteria (equine deverivative: antitoxin after infection), Botulism (equine)^ as a passive inimunization, if it was active one would use inactivated tetanus toxoid and diphteria toxoid. ■   ■ - -
- Against viral infotions: Hepatitis B (human -HBig; after exposure to risk factors (sexual or blood contact) or), Rabies (equine; bitten by potential rabidanimais), Varicelia^zoster (human; given to leukemics, pregnant women and infants that are exposed or infected with chickenppx), CMV (human; given prophylactically for recipients of bone marrow or renal transplants), tick-born encephalitis (human), hepatitis A/measles and other viral infections.
- Against snake or black widow spider toxins , ,    , .       .       i .  „ ■ .   , ,
: ;-l-=-;;a . LasH, c.i-tot '-V'&voftdfts.-'Ww Owm>' $M &^Wv>&w t^odj/aty j/-rf>*&r»*-
-Anti Rh (Antibody againstRhD antigen, given to:Rh- mothers, in a 72 hours peri-natal period to prevent their immization by fetal Rh+ erythocytes that could affect fUture'pregWanc o£W RW>*»fe«te<s cwi-d*avw«<j ^ej«,* iu< s»&cmcw
-Clinical.use of..non-specific immunoglobulin derivates (pooled immunoglobulins), for instance in situations of l.s deciciency treatment.
Anaphylactic Shock. Immunopathological mechanisms, diagnosis,
principle of treatment.
Anaphylaxis is a severe type I hypersensitivity reaction. It is a severe, systemic form of the type I reaction. After an initial exposure "sensitizing dose" to a substance like bee sting toxin, the person's immune system becomes sensitized to that allergen. On a subsequent exposure "shocking dose", an allergic reaction occurs. This reaction is sudden, severe, and1_nvolve5':the^whole^bodv^'Ana"phylaxiS:ls,v/::v::.^«::'-j triggered when an antigen binds to IgE antibodies on mast colls, basophils and eosinphils surface (by its E.cportion) based in connective .': tissue throughout the body, which leads to dcgranulation of such cells (the release of inflammatory/mediators); This can lead to bronchioconstriction and difficulty breathing. ^^-oC'^^j^¥WM}i^^yC^£ Main causes of Anaphylaxis: ^ ^tUchU -h lCAh-\ --=->
-Drugs - penicillins, cephalosporins, proteolytic enzymes, local anesthetics -t-^lUrg       leukocijjDw J le^bttc^O
-Foods - nuts, seafood, chocolate , n  I   ' ■?■£.*'
-Allergen desensitisation, allergen skin tests 1 „ ,        . .
-Bee or wasp sting -   *' ^ ,  - •
-X-ray contrast media, containing iodine (directly activates complement system and there's no prediction marker) Jj. itaees:
1. Sensltisation - production of igE {no symptoms) , '    '*.  -. "    t ,
2. Second exposude - allergen binds to two or more IgE that is bound toma'st cells > degranulation {symptoms present)
r s'       .    '      ; .1 -    - -
Clinical Symptoms: . " -' .
- hypotension (below 90mmHg, secondary to vasodilation) -   - \[ -tachycardia r< :
- dyspnea (cause by bronchioconstriction) _ ,
- abdominal pain, nausea <- "< - - ■
- urticaria on the skin, sweating, itching " .     - • -        - . " .
■contractions of the uterus ,    ,      . ,\ sujelfcfla.
Treatment of anaphylactic shock: ' , - x
-Adrenalin intravenously or intramusculary 10 imicrogr/kg repeatedlyif each vial has .lmg,: one should administer the via! in 3 doses, one every 5 minutes)-which can be lifesaving by reversing the bronchoconstriction and vasodilation effects, it also improves cardiac output, reversing the circulatory collapse. i(v\rnO^A
-Antihistaminics intravenously •
-S    jjphyllin 240mgintravenouslyorinhalation of beta-2-mimetics
-Corticosteroids (200-500 mg of hydrocortisone) intravenously .
-Oxygen M"     .   * " . " -. i
-vasopressor agents (dopamih or noradrenalin)
Atopy. The role of IgE. Mediators of the allergic reaction. Early and late phase of type-l immunopathological reaction.
Atopy = Allergy. The genetic predisposition to production of IgE (type-l hypersensitivity reaction). Thefrequencyof atopy inpeople is approximately 20%. - ■ ,
Probability of atopy in a child :
- Both parents atopics: 80%,
- One parent atopic: 50%, v,.... .■
- No patent is atopic: 15%. * ; IN M0N0ZY60US TWINS-50-60% '
Regulation of IgE production: .    >_\ - '
• Positive regulation: 1l-4 a IL-13 (products of Th2 cells, allergy is a typical Th2 cell} . - "
• Negative regulation: !FNg (product of Thl cells, you cannot use IFNg as treatment) '
BIOLOGICAL EFFECTS OF HISTAMINE -     . '
HI: Smooth muscle contraction, increased permeabihtyof čaptllaries/vaso'diiatatidn/increased production of nasal and bronchial secretions, chemotaxis of leukocytes; hivf-c\\ort>f^<.\^v\ - -/ •
• H2: increase in gastric juice production, increased production of secretions on respiratory tract jSmtid^wuscta ií'ohiÄ'i.^
• H3: receptors present in CNS " _ ; -  * ^
Diagnosis: You cannot use IgE serum levels measuremenlasa reliablediagnosis/ibecause most IgE are bound to mast cells. Must diagnose
by eosinophil number or by skin prick test. 'tcW >\sfc/y\       ,   Hm^Ä-aH-\ _
■ ' -       H'\T'* \ X"
??? CHECK THE SKIN PRICK LUNG VOLUME=GRAPHl!l     "       PfV1    \ / V-/
The main mediators of anaphylactic shock are: ^     o""íď(,0      I li
PREFORMED MEDIATORS: (symptoms caused immediately)
-Histamine (increase smooth muscle contraction, vasodilation and increases vascular permeability -HI receptors; mucous secretion of re   btory^tracrand gastric juice secretion -H2 receptors;H3 receptorsin the CNS)
-Heparin (anticoagulant) "'     - -
-Platelet activation factor;(leads to more histamine and serotonine)
NEWLY SYNTHESIZED MEDIATIONS: (symptoms caused after 6-8 hours) ^ © "\
-Leukotrienes (contraction of brô^chfoles,-íncŕeasectvascular permeability; causes chemotaxis of neutrophils}^ ^rvCA-vVo^^W^Ws^ -Prostaglandin (vasodilation) s| afoplvv wwieit) -
Note: anaphylotoxins- c5a, C4a andc3a complement system, fragments are anaphylotoxic that bind to specific cell seijface receptors and promote,acute inflammation by stimulation neutrophils chemotaxis and activating mast cells. At high concetrations anaphylotoxins activate enough mast cells that can mimic a anaphylactic shock scenario.
Mast Cell Activation Results in:
1) Rapid release of g^nule contents (ta%YyrAirfc,W(}*^)    " c> \ ')
■ 2) Synthesis and secretion of lipid mediators (e itósaŕ&fc: J&)*cfae*t * TSt*ef'
3) Synthesis and secretion of cytokines («?os\^Vl\ eWtrd^t^'^tW)
Other Stimulti which release histamine (other than binding}:
- complement fragments (C5a, C3a, C2a, C4a)
- neuropeptides, bacterial peptides
- cytokines IL-4, IL>6 faulk ^Yxtfirfb^^»^~^b}^fi^ eip^d tiimtda it- L»>,mme <u>:y&-tse -folxu/is-
Phases:
Immediate phase: clinical symptoms evolve in several minutes, mediated by histamine. (^Q\aA - &■[ mail ce.( ts) Late phase: symptoms evolve after 6-8 hours. Mediated mainly by ieukotrines and prostaglandins. UeuJk^ s^rvtye^-A
Examples of atopic diseases:
- Hay fever
- Allergic Rhinitis
-Asthma ^
- Atopic Eczema
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Diagnosis and therapy of atopic diseases
Examples of atopic diseases:
- Hay fever
- Allergic Rhinitis (reactions to inhaled allergens by mast cells in mucosa)
- BronchialAsthma (reactions to inhaled allergens by bronchial mast cells)
- Atopic Eczema - "i^bfn'e^ AfiWtoMvtfcs - ^utv*. ■* ^i^^ du*Ms)h&> ',-$tacf
Diagnostics: ^
-Past history ' -
-Eosinophilia , ■■ -   '•-      -      '    - - "
- Skin prick tests ■       ' , ,
- Provocation and elimination tests -cWt ttrsuMC Same fa&fi     # uikU J-ff& ea'i jfftftr'-^CcV JtU$ A&aetsi»*
Tr- tment:
- anergen avoidance -'
- antihistamine . • , • •     - * ■ .1 • ;.■>..>
- chromons (mast cell membrane is stabilized, must use several weeks before exposure)
- glucocoticoids (anti-inflammatory, highly efficient) . J
- topical steroids (excellent for acthmoji rhinitis)**^ *rtat i^.4^v<Aey«^rffe'),--i-.. :.-=•--•'. -
- antileukotrines (drugs block receptors for ieukotrines).- B2 rec'eptors insmboth-muscles of bonchi, B2 antagonists cause dilation of SM
- allegen immunotherapy (densittsation, by injections of an Ag with increasing doses over extended period, leads to improvement of symptoms, increase synthesis of IgG that can bind before IgE to the Ag). " , 1, -
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- S^tep^ll^ IV   ort    {VUalaW «fr ß^^i^Hcs
Delayed type of hypersensitivity. Tuberculin test. In vivo testing of T-lymphocvte functions. 1
Type IV immunopathologic reactions are entirely celt-mediated (majority are CD4 T-cell mediated); Delayed type hypersensitivity, responses attempt to prevent the spread of infectious organisms by walling them off by forming granulomas, which are composed.of lymphocytes and phagocytes that encase the infectious organisms while they are being destroyed. Takes 2-3 days. Antibodies are not involved because it is mainly intracellular parasites.
Caused by;
1) simple chemicals e.g. nickel
2) plant materials e.g. poison ivy
3) drugs e.g. topically applied
4) cosmetics
Principal mechanism of damage in:
1) Tuberculosis and contact dermatitis; s"     ; -
2) *"^gal, viral, parasitic infections -
3) u^ute and chronic transplant rejection
Mechanism: .(gS+.TcAlt*) ' . ,
APC phagocyte and present Ag to Thl cells that are activated and produce lymphokines: IL2, IFN-y (chcmotactic for macrophages), IL12 (supressesTh2 and expand Thl population), MCF (macrocyte chemotactic'factor):-By this, there isrecruitment of T-cells, phagocytes, fluid and proteins to the zone of infection.A large number-of Macrophages are accumulated, become epitheloid cells and fuse together to form giant ceils (Langhans) granulomatous infection. Macrophagcsexpress ahtigenfragments on their.surfaces in association with MHCI and II and stimulate cTcells and more lymphokines whichleads to a chronicgr%nu\omai:Macrophages!glsodo'not distinguish from affected and non affected cells so they form a lot of collateral damage on healthy tissues.
Crohn's Disease ???
Treatment: Topic drugs (steroids) and iodine.   - ^ _ ,
dth reactions are often used to determine if individuals have been previously exposed to and have responded to an antigen. For instance, a DTH reaction to a mycobacterial antigen (called ppd, for. purified protein:derivative) is an indicator of a T cell response to the 'ftv   .'bacteria. This is the basJS:f0r.ith^-'.RPP skin test, which is frequently used to.detect past or active mycobacterial infection.
Tuberculin Test:     > < +        - - -
A tuberculin skin test is done to see if you have ever had tuberculosis (TB). The test is done by putting a small amount of TB protein (antigens) under tire top layer.ofsk^ to the TB bacteria in the past (Mycobacterium
tuberculosis), your skin will react to the antigens by developing a firm red bump at the site within 2 days.
The TB antigens used in a tuberculin skin test are called purified.protein derivative (ppd). The test is often used when symptoms, screening, or testing, such as a chest X-ray, show that a person may have TB.
A tuberculin skintest.cannot tell how.1ong.you hayebcon infected with TB. It also cannot tell If the infection is latent (inactive) or is active and can be passed to others.
Procedure:
1} Inject intradcrmally.O.lml of tuberculin
2) It Produces a wheal 6mm to 10mm in diameter
3) Do not recap, bend or break needles, or remove needles fom syinges 4}Followuniversal precautionsfprsmfee^
In Vivo testing of t-lvmphocvtes function - MERLEUX MULTITEST:
The Merleux multitest is a commercial test comprising 8 lines with tips containing various bacterial or fungal antigens dissolved in the gelatine. Most individuals have been exposed to these antigens already. The lines are pressed into the skin for intracutaneous delivery. The skin is checked approximately 48 hours later for delayed type hypersensitivity reactions.
1.	Tetanus
2.	Diptheria
3.	Streptococcus
4.	Tuberculin
5.	Contol
6.	Candida
7.	Trichophyton
8.	Proteus
NEOANTIGEN: chemicals bind to directly to intracellular protein causing configuration changes leading to neoantigens (MHC Class I expression > CD8 activation > cytotoxic cell mediated response). Tc. caA\~£
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Immune complex-mediated Immunopathological diseases
Immune complexes are antigen-antibody complexes. They usually form when antigen meetsan;excess ofantibody.vfhese complexes.are cleaned by the classical complement pathway or by the transfer of immune complexes by red blood cells to the liver or spleen for Phagocytosis. The cleaning methods may be inadequate when there is excessive production of immune complexes.     , ' ■}
TYPE iii: antibody mediated reaction like type I and II, but are directed against SOLUBLE antigens.Uses!gGusua!ly,butcan use IgM, Ab-Ag complexes are produced during normal immune responses, if they are not too lalfge they can be cleared by, the reticuloentodthelial system. They cause disease when they are produced in excessive amounts, are not efficiently cleared and become deposited in thetfssues, The Abs within the complexes bind to CI of the complement system and initiate the classical pathway. r '      - -   - - •
Zones affected by the Type lllieactions: . -   -\ ; -   , .
1) GLOMERULI - complement activation leads to damage and possible glomerulonephritis... - - , ' -
2) BLOOD VESSEL WALLS - precipitated complexes can accumulate in the wall a'nd cahinflame^and damage vasculature (e.g.vasculitis).
3) SYNOVIAL MEMBRANES - deposition of complexes and complement activationeancause-destruction.of the join|Ke.g.irheumatoid arth).
4) SKIN-deposition, inflammation and rash -
R;    )ion *   \       ..
1. Complexes formed by cationicAg's bind avidly to negative components of the basementmembrane'of blood vessels and kidney glomeruli, and these complexes usually produce long lasting and severe tissue injury.
2. Complexes may also bind to Fc receptors of mast cellsand leukocytes and activatethem to'secretexytokines and vasoactive mediators.
3. Neutrophils ingest the complexes and release degr.ada'f^ and collagenases, .which damage the tissue. Neutrophils together with platelets begin to pile up at the site of.reaction.leading tostasis of blood, andblockage occurs, ending in haemorrhage and necrosis of local tissue.             _        .            "      *     . , - I
Typical disorders resulting from Type Ml:
SERUM SICKNESS: e.g. horse antidiplheria toxins   bfoo& %?ncftt^Vi Following the injection of foreign serum/the antigen isexcreted slowly.During this time, antibody production starts. Presence of Ag-Ab leads to formation of immune complexes "which may be deposited at various sites. It can result in: fever, uticaria, glomerulonephritis, etc.
IMMUNE COMPLEX GLOMERULONEPHRITIS {poststreptocpccaij   i   . ':' ■
Damage to the glomerulustsfollowing deposition of immune complexes that may form as ar&sult of certain viral or bacterial infections. Rl    MATOID ARTHRITIS (autoimmune) ^IfjM
Serum and synovial fluid contain rheumatic factor. IgM and lgG bind to normal. IgG Fc fragment, which leads to deposits of immune complexes on synoviafmembranes and blood vessels. This leads toactiyationofthe complement, causing inflammation.
SKIN RASHES: • ^ \   I  , ■     ,, „■ L,A 4--' ~p
Immune complex deposition in various sites of skin     . . •;- I
SYSTEMIC LUPUS EYTHREMATOSUS :
A systemic disease complex clepositionand inf!ammation:spread all over the body. It arises from Abs formed against DNA, RNA or chromosomal proteins. • •   :. • ••    ..... . •••
Type Hi'hypersensitivity
Immune complex measurement in serum: (fc.CO ;lmmune.compIexesare usually cleared by phagocytic cells in the spleen and liver. Most complexes are bound to RBC which transport them .We add REG (polyethyl glycol) to decrease their solubility. Complexes are precipitated and by photometry we can measure the precipitation intensity of opalescence.. , .... . '
Direct Immunofluoresence:     •    <■ -
For detection of antigens. We react^ffthe tissue with fluorescently labelled specific antibodies. Therapy: control of inflammation, and antiCD20 to control B-celis population.
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Autoimmune reactions: mechanisms of triggering the autoimmune
reaction. Genetic and Environmental influences.
Autoimmunity is an immune response against self (auto) antigens, and is an important cause of disease. The principle factors.in ther^x development of autoimmunity are the inheritance of susceptibility genes, which may contribute to failure of self tolerance and environmental tiggers (such as infections), which may activate self-reactive lymphocytes. The auto-reactivity is by T-cells or antibodies.
Mechanisms:
1. Cross reaction with microbial antigens - some microorganisms have epitopes which also occur on self molecules;*;i : s-v.
2. Polyclonal activation^- some infections such as malaria can polyclonally activate B-cells, including self-antibodios.
3. Alteration of normal proteins - drugs can bind to normal proteins and make-them immunogenic e.g. PROCAINAMIDE > SLE
4. Release of sequestered antigens - sperm, ens, lens etc are all sequestered so their antigens are not exposed to the immune system.
5. Supresslon of suppressor T-cells-by drugs, or in elderly patients. _ j
Autoimmune diseases are usually multifactorial. Combination of events probably requires both genetic and environmental factors. GENETIC FACTORS: \    ,  ''        ~       ,     - -
G" jtic predisposition to autoimmune disease; inheritance is polygenic so there is arilnvolvement.ofvarious genes. One gene family that involved is the HLA complex (important in their recognition bytheTCR):-Examples: .
C^cW-O^OSO^VJi   fa "
Ankylosing Spondylitis     B27 - HL({ ^X2- '    ' '    ' .
Type 1 Diabetes DR3/DR4"] .i
Rheumatoid Arthritis      DR4    J   & I  -EC- • ; •
ENVIRONMENTAL FACTORS:
a) Hormones - females are more prone to developing autoimmune disease, which usually have thetronset in reproductive years
b) Infections -molecular mimicry , ~
c) UV radiation - can modify self antigens and enhance their immunogenicity    . .
d) Drugs - some drugs bind directly to the peptide containing groove on MHC molecules and induce abnormal T-ccll response
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I m m une Tolerance
Immune tolerance is when the immune system recognises an antigen antigen can have three possible outcomes: -Activation of lymphocyte
- Tolerance (inactivation or killing of lymphocyte}
- ignorance
interaction between a lymphocyte and
It is determined by the nature of the antigen-specific lymphocyte, the are that it prevents unwanted reactions, trets allergiv/autoimmune di
Mayed. The advantages of immune tolerance splant rejection.
Central Tolerance:
- Negative selection during thymic education
- Deletion of autoreactive B-cells in bone marrow
Peripheral Tolerance:
inT-cellsisdueto:
- C'-->al deletion (stimulation by antigen > apoptosis by Fas-Fas ligand
- C.v-,ial anergy (no co-stimulation of CD28 by B7 of APC)-}      ^ -c
- Clonal Ignorance (not enough Ag, insufficient stimulation) :--Supression by regulatory t-cells (secrete 1L10 to inhibil macrophages In B-cells is due to:
- absence of costimulation from specific Th cells Regulatory T-cells:
Treg cells: inborn tolerance, develop in the thymus
Trl, Th3: peripherally induced, ivolved in acquired tolerance
Acquired tolerance: -  -   ■    ^     '     • =
LOW ZONE TOLERANCE - repeat injections:of low dose Ag > stimulate HIGH ZONE TOLERANCE - high doses of Ag > clonal deletion
Mechanisms of breaking immune tolerance:
- Visualisation of hidden Ag 1
- Af^y^Nl^jfrcft self-antigens by chemicals/burns/necrosis
- C, _ jí rea?ffvity of antigens        - '
- Defect in suppressor function of lymphocytes
- Excessive stimulation of the immune system
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Laboratory tests for detection of autoantibodies. Antinuclear and other clinically important antibodies
Antinuclear antibodies :-.^y:,-i;^:>;-.-vi.,/: ■■ ;z.:■>■:-::
- antibodies directed against contents of the ceil nucleus . ~ • * • ••
- are present in higher amounts than normal In autoimmune diseases - . . • • -ANA tests can be used to measure the pattern and amount of ANA which is useful for aiding diagnosis - :; ■ : -
- detecting presence of AN A is a good screening test for SLE (prevalence is almost 100%)    , '/
1) Sample of tissue drawn from patient (containing ANA) and mixed with serum of patient <     -   - __ '--
2} ANA will binjf to the cell nuclear parts     ,           ^                    >~"~'-  -              -- " ' ^
3} A seconds antibody with fluorescent dye is added, and binds to the ANA-antigen complexes : " -     - _ _"    -     ":
4) Viewed under UVmicroscope                                                     V •''          '' • \ * .':"./     " '"'
Poa.j'vitv of ANA: ,.•  .... 'v..' . : ■ \
SLE - 95-100%' , '   _" _m -
Rheumatoid Arthritis -15-30% r^^^i^^^MM^'k       ^; V;;. .'
Autoimmune Hepatitis-20-60% :    • .  ' '       .. .        \r■'■ .■
Healthy Persons-0-4% 5 ,     : ~~
Elderly-10-20%     .   . \:L\V;/-V •/•'
Systemic Lupus Erythematosus:
-women to men 10:1 "       ;'-'',*  1 ,
-starts in early adulthood ..:/'••'      , ■ '   *:.v* •.
- predisposition with HLADR3 * •    .. , .
- symptoms: fever, weightloss, butterfly erytHerna;:aJoR^ joint pains
- most symptoms are cause by deposition of immune complexes •: .•; r **  v-v • •-" ,
Other clinically important antibodies: .   " ,
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Transplantation Immunology
AUTOGRAFT; from one part of the body to another
ISOGRAFT: between genetically identical individuals (monozygous twins)
ALLOGRAFT: between members of the same species
XENOGRAFT: from a foreign species
Rejection:
HYPERACUTE - antibody mediated - occurs within a few minutes
ACUTE - T-cell-mediated - occurs after a few weeks - REVERSIBLE BY IMMUNOSUPRESSION CHRONIC - both antibody and cell mediated - occurs after years
Most frequent types of organ transplant: Ratio of success t5 year graft)
Kidney: 80-90% ^_ r .
Heart: 70% ' Lung:40-50%.
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Kidney transplant: living donor can give one, and recipient can wait by dialysis-.  \        , ^. ,
Heart/Liver transplant: URGENT, need negative cross match and same blood group (heart doesn't display many HLA antigens)
Lung transplant: used only in terminal stage, bad results - 50% live 1 year, 5 years max
Pancreas transplant: endocrine part is transplanted ' •
Bone marrow transplant: " . - '     ~    . t i
- can use whole bone marrow or just haematopoetic stem cells (CD34+)
- used in bone marrow failure and primary immunodeficiency
- can cause graft vs host reaction (in allogenic transplant when functional immune cells in the transported bone marrow recognise recipient tissue as foreign and mount an attack,;common targets are liver, skin and G!T) •
Compatibility Tests:
- ABO group
- HLA typing ->■■.
- C    ^ m^cfling: must be negative - recipient serum should not kill donor leukocytes (MHC Class-I Ag vs Ab in serum)
Immunosupresslon: .-j-v*;,
- high dose steroids
- anti lymphocytic serum - ,
- monoclonal antibodies (antiCD3, antiCD25 - Inhibits regulatory t-cells)
- alkylating agents
Immunological aspects of blood transfusion. Polysaccharide and protein blood group antigens. Adverse reactions to transfusion.
Transfusion is a transplantation of circulating blood cells, platelets or plasma fom one individual to another. They are.performed to treat blood loss due to haemorrgae, or to treat a deficiency in one or more blood types.
The major barrier to transfusion Is the presence of foreign blood group antigens:
Polysaccharide antigens of blood group antigens: ~ .
- most important is the ABO system {determined by 2 loci, H locus and ABO locus (C9»   - '
- in rare occasions, patients can have BOMBAY PHENOTYPE where the H substance is not present
-the H substance is the core substance of the ABO antigen ■/        * -   - - >: _
- igM antibodies detect A/B antigens, and they are present even without Ag stimulation '    -.    ■  '     , ■
Phpnotype_ Genotype_Antibody In Serum_
f '
A AA/AO Anti-B ' _ -
B BB/BO Anti-A   -' " 1
AB AB (u. Recipient) none -
O 00 (u. Donor) .    Anti-A/B '
Protein antigens of blood groups: . . % -
- most important is Rh system -  ■ .
- Ab of IgG isotype, and develop after Ag stimulation -
- Rh- can develop antt-Rh antibodies after exposure to Rh+ blood cells
-can be a problem when the mother is Rh- (in second pregnancy/treated by injection'of anti-Rhantibody)
- minor protein blood groups =_Lewis, Kelly, Duffy
A    ?se Reactions:
HAEM0LYT1C - headache, myalgia, nausea, fever, haemoglobin ciasts causing kidney failure FEBRILE-antibody against minor blood groups • ALLERGIC ■ urticaria^bronchospasm^anaphylactic shock .
TRALI SYNDROME ^dyspnea/cough aftertransfusion caused by thrombocytic aggregation in lungs
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Immune reactions between mother and foetus. Immunology of reproduction.
For the mother, the foetus represents a kind of allogenic transplant against which an immune response must be suppressed.'
l^ln a normal pregnancy, humoral immunity prevails, due to an increased release of Th2 cytokines. This blocks function of Thl ceils which protects the foetus from cell-mediated attack.
^Progesterone induced production of PIBF (progesterone induced blocking factor) which suppressed proliferation of Iymphocytes4 activation of NK ceils and TNF.
^)A!fa-feto protein from the foetus causes immunosuppressive effects on the mother.
^Blockage of lymph nodes which drain the uterus prevents antibodies entering the circulation.   - "- -
j)Human chorio-gonadotropin (HCG) has a negative charge which repels the mothers immune ceils.' J '
jjNo classical HLA antigens are expressed, but this makes the trophoblasts a target for NK ceils. Therefore, the trophoblast expresses HLA-G antigens which bind with inhibitory receptors on NK ceiis, leading to theirsuppression. Fa,s.lteand is also expressed on trophoblasts which kills T-ceils. * - s: :      , "
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Immune system and tumours. Protective mechanism against tumours. Immunological diagnostics and treatment in oncology.
Immune surveillance is a physiological function of the adaptive immune system, to prevent outgrowth of transformed cells and to destroy these cells before they become harmful tumours.
Tumour antigens:
TSA: tumour specific antigens - newly developed antigens v-^v:. TAA: tumour associated antigens - normal antigens with increased malignancies
Tumour antigens in different types of tumours:
VIRUS INDUCED TUMOURS: antigens are virus specific CARCINOGEN INDUCED TUMOURS: no inducer related specificity
SPONTANEOUS TUMOURS: antigens are variable ' ' .  ' - . -. -
Immune response to tumours: - ~
- cytotoxic T-cells i -t   Jells U'KceUU. / -ADCC - - -
- activated macrophages -      • •. .•
Protective mechanism of tumours: -  - - - .••      • •
- low immunogenicity of tumours - - -
- low expression of HLA-1 ■   " -■ _
- antigen modulation
- immunosupression = prostaglandin, IL10,TGF-B like cytokines   • .; v.. v   •••••••• /
-large tumour mass
Immunodiagnostlcs:
- detection of tumour associated specific antigens -monoclonal gammapathy (Paraproteins) -alpha-feto protein (in hepatocellular carcinoma)
- c-'-jonembryonic antigens
- iii.iriunophenotyping of lymphoid malignancies w-x*-:^^;:-: Therapy:
Immunotoxln therapu
Cytokines - IFNa blocks protein synthesis, il2 stimulates T-cells, TNFa Vaccination - by mixing tumour antigens with dendritic cells :> Monoclonal antibodies
Lymphokine activated cells, cultivated with IL2 and given back to the patient Paraproteins:-
* Monoslonal immunoglobulins in human serum.
' MaiigSant-in myleoma ■>-~>^;,i;y -il ^j~^-Beh)^^H)^nlv'in.oM. people, patients with chronic inflammation, idopatic (MGUS - monoclonal gammap&thy of unknown
significance)   ; •     •        . .
Detected by imunoelectrophoresis, immunofixation Myeloma: '■>^^v^^,-s--^:'y7.rt?:i-'-;\^;Vv:-;.;^:..
Tumor that evolves from plasma cells
♦ Paraprotein in serum
• Increase in plasma cells in bone marrow
♦ : • Kidney failure
• Pathologic fractures
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Immunity in childhood and in elderly.
Immune system In infancy and childhood:
Increased susceptibility to infectiousns diseases.
• Clinical course of infections are usually mild.
Exception - severe course of infections caused by encapsulated bacteria during first two years. Atopic diseases usually begin in early childhood.
• Autoimmune diseases are relatively rare. : -;r■-v^■■■■■i,
Immune system in adulthood:
• Infectious diseases are infrequent, but may be severe in course.    - -Autoimmune diseases typically begin in early adulthood.
• High prevalence of allergic diseases continues from childhood ' .   . r
Immune system in elderly:
• Weak primary Immune response, secondary immune response is Usually normal. •\^.::v^^'k^r-,i-k.^'.
• Decrease in lymphocytes, mainly CD4+, serum immunoglobulin levels are'usually increased.-.■
• Immune response is generally decreased, clinical symptoms of infection are milder than in young persons.
• Diturbed regulation of the immune system leads to frequent occurrence of autoantibodies and paraproteins, but this does not lead to clinical diseases.
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Manipulation with the immune system - immunopotentiation, immunosuppressive agents
Immunopotentiators, also known as immunostimulators, are substances (drugs and nutrients) that stimulate the immune system by inducing activation or increasing activity of any of its components. One notable example is the granulocyte macrophage colony-stimulating. factor (a protein secreted by macrophages).
There are two main categories of immunostimulants:
• Specific immunostimulants are those which provide antigenic specificity in immune response, suchas vaccines or. any antigen.
• Non-specific Immunostimulants are those which act irrespective of antigenic specificity to augment immune response of other antigen or stimulate components of the immune system without antigenic specificity, such as adjuvants and non-specific immunostimulators. Usually with microbial or mammalian cell products. E.f. DNGB  dinitrochlorobenzene at thesite of tumour leads to diminish in the size of some cutaneous malignancies.  '' -. - '
Immunosupression: . .   - _ <
Immunosupressed agents, suppress the entire immune response in a non antigén specific wayŕUsuaily'usedafter transplantation or in se   y autoimmune diseases. -
Antiinflammatory agents: CORTICOSTEROIDS (stabilise lysosomal membranes thus preventing the release of lysosomal cells, inhibit activity of inflammatory cells, and inhibit t-cell cytokine production     ' i
ANTIMETABOLITES: - '
Purine antagonists-impaire synthesis of purinenucleotides and soinhibitDNA synthesis
Alyklating agents - react with bases of nucleotides and prevent cell division by, cross linking the two strands of the double helix Antifolates - e.g. cyclosporins - causes reduction of.cýtokine:productip'n (IL2/1L4) andsynthesisof IL2 receptors
Monoclonal antibodies (antíCD3, antlCD20) ! '
Antilymphatic serum (polyclonal antibodies against lymphocytes)
PLAŠMAPHORESIS: removing individualsblood, separating components, REMOVING PLASMA, and returning the cellular components. Used in autoimmune diseases such as Good Pasture's syndrome/Myasthenia Gravis/etc- It is used also for collection of specific Ab rich plasma for use as ISG (immune serum globulin).
B?  ^rial immunomodutators •
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Serum. Classical serological reactions: Agglutination, precipitation.
Serum is the celi-free fluid that remains when the blood or plasma forms a clot, It is the blood plasma WITHOUT fibrinogen.
To prepare it we need to take the patient's blood and let it clot for about 1 hour. The serum will appear on top.
Antisera-antibodies are obtained from animals (rabbits, goats, horses) often repeated immunisation by antigens. They are markedly polyreactlve antibodies which bind many epitopes of the antigen but also with other antigens: There^are advantageous in the classical serological reactions. - ■
Monoclonal antibodies are artificially created antibodies and are prepared from infusions of B-cells from an immunised mouse with myeloma cells. These produced antibodies are strictly monospecific, a,nd therefore cannot be used in classical serological reactions." .
Antigen and antibody (from serum of patient of antiserum from animal) > reaction '  . •
Two phases of a serological reaction: !. - -
Primary phase - concrete antibody binds to a concrete epitope = specific phase of the reaction Secondary phase - visualisation of the fact of previously occurred primary reaction
Ay   itination reactions: "  J "' '
Immune complexes form (corpuscles are clumped together, morphologically expressed as agglutinate),due to reaction between
ANTISERUM and CORPUSCULAR ANTIGENS. Direct agglutination (e;g.-haemag!utination) or Passiveagglutination (e.g. latex agglutination).
Hemagiutination: . J-s \'
-detection of agglutinating antibodies in serum sample ' ' " -
- complete antibodies are immunoglobulins of the igM c!ass;~bindtng to antigens of RBCs, and they Induce agglutination
- they care called complete antibodies because they caninduce agglutinationdue to their pcntameric structure -incomplete antibodies bind to the antigen epitope but cannot induce agglutination -
- hemagiutination can occur when the distance between.RBCs:is reduced by adding a supplement (albumin) to a solution with a low ionic charge .       -  1 .
Causes of no agglutination: monovalent antibodies (IgAl);* repulsive forces betweenantlgens, low number of bridges between antigens We can visualise agglutination with a Coombs test: ->
DIRECT COOMBS TEST: detection of antibodies bound to surface of erythrocytes; in a Rh-1 mother pregnant with a Rh+ child, the foetal cells in the mother are coated with maternal antibodies. We add rabbit anti-human antibody (Coombs serum) causing agglutination.
INDIRECT COOMBS TEST: detection of antibodies in circulation. In Rh- mother serum, aAUh+ erythrocytes and wash out the unbound antibodies. Add coombs serum tocause agglutination.
Positive Coombs test: patient hasantibodies against erythrocyte surfaceantigens.
Precipitation: -
Reaction between polyclonal antiserum and soluble antigen. A complex lattice of interlocking aggregates is formed. Turbidimetry: Ag sample placed in cuvette and allowed to react with excess antiserum, soluble immune complexes are formed. Nephelometry: also based on reaction of soluble immune complex, placed in a cuvette and scattering of light is measured.
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