Immunity Pavel Hyršl • Immunity • Self - and non-self recognition / protection against – foreign macromolecular substances (proteins, polysaccharides) – pathogens (bacteria, viruses, fungi, protozoa, nematodes, flatworms) • Immune system – nonspecific immunity - uptake of pathogens by phagocytic cells, release of defensive proteins – specific immunity - lymphocytes infection immunity Balance between infection and immunity Immunology originated from microbiology • planet of microorganisms, almost 3 billion years without other organisms, the carbon bound in microorganisms is twice as much as in all other organisms • microorganisms are ubiquitous as pathogens, symbionts, commensals… inseparable from higher organisms (including the genome) • 1-10 bacterial cells per 1 human cell, 1-1.5 kg of human weight, about 1000 species, 1 g of soil contains 109 bacteria in 7,000 species • during diseases the number of species of intestinal bacteria is reduced, changing the composition of species can significantly facilitate healing probiotics (bacteria of lactic fermentation, e.g. lactobacilli, bifidobacteria) + prebiotics (support growth of beneficial bacteria, such as carbohydrate components - inulin), synbiotics - contain pro- and prebiotics • fecal transplantation of microbiota to patients with intestinal infection • life without bacteria is complicated - immature immunity • antibiotic resistance is 30,000 years old - ice samples - resistance genes are common in the environment, there are bacteria resistant to up to 100 antibiotics) • The microbiome that inhabits the skin, respiratory tract, urogenital and gastrointestinal tracts is the primary regulator of health and disease. • Even on the surface of the skin of a very clean person live up to tens of grams of various types of bacteria and other microorganisms, after washing their number decreases, but soon reaches its original values. • The ability to defend integrity is called immunity (in plants and microbes often as resistance). High quality rearing of insects https://www.youtube.com/watch?v=WEtJYXsYKxc Organs of the immune system https://media.healthdirect.org.au/images/inline/original/organs-of-the-immune-system-illustration-18584a.jpg Primary lymphoid organs • Bone marrow – Stem cells • Myeloid precursors • Lymphoid precursors • Thymus – Two types of tissues • Cortex • Marrow area Secondary lymphoid organs • Spleen – It absorbs microbial stimuli from the blood • Red pulp (larger) - macrophages • White pulp - T and B lymphocytes • Lymph node – Here, IS cells encounter the antigen – Development of a specific immune response https://training.seer.cancer.gov/images/anatomy/lymphatic/lymph_node_structure.jpg Mucosal immune system • MALT (Mucosa Associated Lymfoid Tissue) • GALT (Gut Associated Lymfoid Tissue) • BALT (Bronchus Associated Lymfoid Tissue) • this means that the immune cells are in the blood, but also on the skin, mucous membranes, genitourinary tract, etc. (protects huge areas) • forms the interface between the organism and the external environment Figure from Carr & Rodak, 2012 (15). Cells of the immune system • Neutrophil granulocytes – they live very shortly in the blood, performing functions quickly and breaking down – primary protection against extracellular bacteria – phagocytosis (intracellular killing), function in primary inflammation – CD66 positive, Cluster Designation (sometimes also referred to as cluster of differentiation) • Eosinophilic granulocytes – defense against large parasites (protozoa, tapeworms) – release of lytic enzymes from the granules – apply in allergic reactions • Basophilic granulocytes – in granules heparin and histamine: function in inflammation (dilation of blood vessels) – specific / adaptive immunity Cells of the immune system • Monocytes (mobile) → macrophages (tissue) – phagocytosis of pathogens / cancer / apoptotic bodies, tissue regeneration – APC: antigen presentation (specific / adaptive immunity), MHC-II proteins – CD14 positive, adherence to glass and plastic – production of cytokines – defense against extracellular and intracellular pathogens • Dendritic cells – APC in tissues - uptake Ag – node migration, presentation APC and development of immune responses • Mast cells (heparinocytes, mast cells) – tissue equivalent basophils Cells of the immune system - LYMPHOCYTES • T-lymphocytes (CD3 +) – management and decision-making in IS – Subpopulation - Th (CD4 +) Tc (CD8 +) Treg • B-lymphocytes (CD19 +, CD20 +) – antigen reception, processing and presentation (APC) – able to process soluble Ag (compared to other APCs) • NK cells (CD56 +) – they look like T-cells but they don‘t have T-cell receptor (CD3-) – recognition and disposal (such as Tc) low expression / MHC-I sites (i.e. tumor sites, virus-infected cells) https://www.youtube.com/watch?v=AucZlvEv29Y Vertebrates: - pathogen-host relationship: greater variability means greater resistance (however, an extreme increase in variability is detrimental) - looking for sexual partners: better coloring means more offspring - by smell they are able to recognize a suitable combination of genes, related individuals are less attractive MHC genes (from cartilaginous fish) Toll-like receptors (from bony fish) - study on birds - paternity of young in permanent pairs - rodent studies Immune-relevant molecules Molecules in IS - differentiation of "own" from "foreign" = MHC • The body's cells carry proteins on the surface MHC – Major Histocompatibility Complex (also "HLA“- Human Leukocyte Antigens) – ALL the cells of the body carry MHC-I – APC the cells carry extra MHC-II (have MHC-I + MHC-II) • Function MHC - mark of cell affiliation to the organism - processing and exposure Ag - MHC-I → CD8+ T-cells - MHC-II → CD4+ T-cells • Variability in structure of MHC - genetic "relationship" → possibility of organ transplants • IS cells - they will learn to recognize their own MHC (T-cells, NK-cells) - they can recognize MHC with bound of Ag and respond (T-cells) - "foreign" MHC in the body: very strong reaction (transplantation) In Drosophila dual function - dorso-ventral axis in embryonic development and immunity… This is crazy, das ist toll !!! Overview - The main molecules of the immune system • Glycoproteins of MHC Classes I and II (= HLA in humans), TLR receptors - see before • Ag-specific receptors on the surface of T- and B-cells (TCR/BCR) • Antibodies (Ab) / Immunoglobulins (Ig) - B-cells • Receptors for Fc fragments of Ig - different cells • Cytokines - different cells in the body • Receptors for cytokines - different cells in the body • Complement & receptors (different cells in the body) • Adhesive molecules • Costimulatory molecules • Interleukins Innate / Nonspecific immunity non-specific immunity: – evolutionarily older, it occurs in various forms throughout the animal kingdom from invertebrates to mammals basic characteristics: – is congenital • the organism has it from birth • it does not matter whether it has encountered the disease or the pathogen – is not specific • the cells act in the same way against all foreign particles – has no immunological memory • the action against the antigen is always with the same force, even if it is repeated 21 Non-specific immunity – skin: • the boundary layer separating the organism from the external environment creates an unfavorable environment for many microorganisms • mechanical protection • sweat - bactericidal (organic acids, urea, salts) – mucous membrane: • enzyme lysozyme in saliva and tears • HCl in the stomach • acid secretion of the vagina • mucus on the surface mucus respiratory and digestive tract – phagocytosis: • uptake of foreign material by specialized cells – monocytes, macrophages, eosinophilic and neutrophilic granulocytes 22 Ilya Mechnikov term used for the first time phagocyte Origin from Greek words phagein - to eat cytos - cell The cellular nature of immunity Beck and Habicht 1996 • process in which specialized cells of the organism, called phagocytes, recognize, absorb and process foreign material (> 1 m) after its penetration into the body • the oldest and most effective mechanism of nonspecific immunity from unicellular to vertebrates • an integral part of the physiological reactions of the organism • it is subject to the control signals of other components of the immune system and other physiological systems • phagocytes form mediators acting on other components of the immune system or other physiological systems Reasons: nutrition, development and formation of tissues, immune reactions, repair of damaged tissues Endosymbiotic theory…. https://www.youtube.com/watch?v=7VQU28itVVw Phagocytosis http://highered.mcgraw-hill.com/sites/0072495855/student_view0/chapter2/animation__phagocytosis.html http://www.youtube.com/watch?v=fpOxgAU5fFQ Microbicidal mechanisms Independent of oxygen • acidic pH in a phagolysosome • acid hydrolases, neutral proteinases • granular cationic proteins (eg phagocytin): damage the cell membranes of bacteria, inhibit their respiration • lysozyme: cleaves -1-4-glycosidic binding of bacterial cell wall polysaccharides • lactoferrin: stops the growth of bacteria, supports the effect of lysozyme Dependent on oxygen • myeloperoxidase dependent and independent https://www.bio-rad-antibodies.com/blog/how-macrophages-make-tattoos-last.html Ink phagocytosis… A visible example of phagocytosis… Non-specific immunity – natural cytotoxicity: • release of perforin - substances causing perforation of the target cell membrane • natural killers NK cells = natural killers – non-specific defense against viruses and tumor cells – recognize pathological changes on the cell surface • non - specific tissue response to irritation or infection INFLAMMATION • phagocytic cells penetrate the affected area • increase in blood sedimentation • purulent inflammation - pus - white blood cells • ending - ITIS, ITIDA (bronchitis, encephalitis) • pyrogens (from leukocytes) - fever – leukocytes acting on the thermoregulatory center in the hypothalamus + general nausea → increase the effectiveness of the immune system 30 Inflammation ▪ increased blood flow and dilation of capillaries allow phagocytes to penetrate the wound site ▪ macrophages phagocytose pathogens and cleanse damaged tissue cells, pus are dead phagocytes, proteins and fluid from the blood capillaries Beck & Habicht, 1996 Specific / adaptive immunity specific immunity: – realized by lymphocytes – production of antibodies - formed against antigens • antibodies = proteins - immunoglobulins distribution: – humoral immunity: • antibodies produced by B – lymphocytes – cellular immunity: • T - lymphocytes 33 Humoral specific immunity humoral immunity: 1. B cells recognize the antigen 2. antigens react with protein binding sites (receptors - immunoglobulins) on B cell membranes 3. cells multiply - proliferation 1. plasma cells - active stage of B lymphocytes, producers of antibodies against the given antigen (pathogen) → primary immune response 2. memory cells - they live for a very long time, they condition a rapid immune reaction (antibodies) when they meet the same antigen again → secondary immune response 34 https://www.immunology.org/public-information/bitesized-immunology/immune-development/b-cell-activation-and-the- germinal-centre Secondary immune response ▪ if a person encounters the same antigen later in life, the body's response is faster (2-7 days) and sharper and takes longer antibodies Sibernagl, Despopoulos, 2003 https://www.thermofisher.com/ - The origin of adaptive immunity is accompanied by the RAG-1 and RAG-2 genes (recombination activation genes). - They encode recombinase enzymes - rearranging gene segments for the antigen binding site on an immunoglobulin molecule, thereby generating diversity. - Probably transferred horizontally from bacteria. - They are only in lymphocytes, in no other cells ... Cellular specific immunity cellular immunity: – T-lymphocytes, Th, Tc, Treg – no antibodies are formed – antigens presented by other cells binds to T-cell receptors - followed by direct contact with a foreign cell - destruction of a foreign cell – part of the cells remains - memory – they can reduce tumor growth - they cause non-acceptance of transplants organs (immunosuppressive substances) – regulate the activity of B-lymphocytes 39 https://teachmephysiology.com/immune-system/cells-immune-system/t-cells/ Blood groups • more systems - best known: AB0, Rh-factor • AB0 – structures on the surface of blood cells = agglutinogens • A and B, act as antigens – plasma antibodies = agglutinins • anti-A and anti-B, cause clumping of blood cells - agglutination – 4 blood groups according to agglutinogen • A, B, AB, 0 system AB0 • representation of blood groups – different in different parts of the world – from west to east decreases A and B increases – A have the Eskimos and Lapps – Koreans have the most B – Indians have at most 0 (up to 100%) Blood group / percentage Rh factor • another agglutinogen Rh (macaque rhesus) • anti-D antibodies • Rh+ a Rh- (about 15% of the population) • problems during pregnancy – Rh- mother a Rh+ child – first pregnancy - blood mixing → formation of antibodies in the mother's body → second pregnancy → antibodies damage the fetus, premature births → examination of mother and father Rh factor and pregnancy ◼ Hemolytic disease of newborns Diseases, illnesses and disorders • allergies, allergic reactions: – caused by hypersensitivity to otherwise generally harmless substances, so-called allergens – typical local manifestations: redness, swelling, itchy skin, sneezing, vomiting, diarrhea, urticaria • autoimmunity: – failure of the ability to distinguish foreign substances from the body's own substances - the formation of antibodies against its own tissues • multiple sclerosis (disruption of myelin sheaths in the CNS), haemolytic anemia (antibodies to erythrocyte antigens • AIDS: – agent retrovirus HIV - attacks T-lymphocytes • tumors – in addition to foreign pathogens, the immune system must recognize its own abnormal cells and then eliminate them – in the case of tumors, this mechanism fails 45 Failure of immunity • many variants of immunoglobulins • vaccination → immunization - active immunization - insertion of killed or weakened microorganisms - passive immunization - insertion of antibodies Immunization http://www.glenfieldmc.co.nz/services/fundedimms/ Phylogeny of immunity http://www.ocw.cn/OcwWeb/Biology/7-345Spring-2005/CourseHome/index.htm Examples of final exam questions for Immunity: 1. White blood cells - list their main roles in the body and types (without details of immune reactions). 2. Characterize the specific immunity of mammals. What is the specificity based on, which cells, meaning. 3. Characterize the non-specific immunity of mammals. Which cells, meaning. 4. What do you know about the powerful components of innate (non-specific) immunity? 5. Characterize the cooperation between the nonspecific and specific mammalian immunity. 6. Characterize B-lymphocytes and their function in the mammalian immune system. 7. Characterize T-lymphocytes and their function in the mammalian immune system. 8. Characterize antigen presenting cells and their function in the immune system. 9. Compare the immune mechanisms of invertebrates and vertebrates. 10. Describe the principle of the Rh group system and its importance in pregnancy. 11. According to what abilities can the performance of the immune systems of animals be compared? Characterize the evolution and variation of immunity in major animal taxa. 12. Describe the immune basis of blood groups. What happens in case of incompatibility. How does AB differ from the Rh system immunologically? 13. What do you know about the powerful cells of the immune system? How are they activated and how do they participate in specific immune responses? 14. Describe the relationships between microorganisms and vertebrate immunity. What is the microbiome? Localization, recognition. 15. How are specific and non-specific immune cells activated? 16. How does the immune system of mammals distinguish foreign structures from their own? How does it "know" which is foreign and which is own? 17. What diseases and disorders of the immune system do you know? What do you know about them?