1. DEFINITION AND PROPERTIES OF ANTIGEN IMMUNOLOGICAL DEFINITION Any chemical structure Soluble or corpuscle Simple or complex Originated from the body or comes from outside Genetically self or non-self Natural or artificial

2. DEFINITIONS ANTIGEN (Ag) - any substance, which is recognized by the mature immune system of a given organism to bind specifically ANTIGENICITY– capability of an antigen to bind specifically with certain product of the adaptive immunity: TCR or BCR/antibody, induce –immunogenicity - capability of an antigen to induce an (adaptive) immune response, –tolerogenicity - capability to induce immunological tolerance, specific immune non-responsiveness

3. FACTORS INFLUENCING IMMUNOGENICITY I. Foreignness Size Genetics –Species –Individual Age

4. FACTORS INFLUENCING IMMUNOGENICITY II. Dose Route subcutaneous > intravenous > oral / intranasal Not true for live vaccines (i.e. oral polio vaccine) Adjuvant –substances that enhance an immune response to an antigen (aluminum salts, LPS, Freund’s adjuvant, TLR ligands) COMPLEX EFFECTS –depot effect – slower biodegradation, prolonged antigen intake by antigen presenting cells –activation of innate immunity

5. FACTORS INFLUENCING IMMUNOGENICITY III. Physical status –corpuscle (cell, colloid) or soluble –denatured or native Degradability –antigen presentation by APC

6. part of the antigen which is recognized by a defined immunoglobulin (BCR / antibody) or by T cell receptor ANTIGENIC DETERMINANT (=EPITOPE)

7. BCR (mIg) Ig (antibody)

8. Ab1 Ab2 hidden/revealed determinant denaturation new/neoantigen determinant conformational determinant cleveage conformational/linear determinant TYPES (STRUCTURE) OF ANTIGEN DETERMINANTS surface/accessible determinants linear determinant conformational determinant (TCR, BCR, Ig)(BCR, Ig)

9. B cell epitope T cell epitope recognized by B cells proteins polysaccharides lipids DNA steroids etc. (many artificial molecules) cell or matrix associated or soluble recognized by T cells proteins mainly (8-23 amino acids) requires processing by APC

10. ANTIGEN RECOGNITION ≠ CELL ACTIVATION

11. ANTIGEN RECOGNITION BY NAIVE T CELLS REQUIRES PRESENTATION VIA MHC MOLECULES Recognition/ No activation Recognition/ Activation

12. SUPERANTIGENS Microbial proteins that bind to and activate all the T cells that express a particular set or family of TCR molecules resulting in a polyclonal activation. Interaction is not via the peptide binding cleft of MHC molecule. Hypotension Rash Desquamation Fever

13. conventional antigen monoclonal/oligoclonal T cell response 1:10 4 - 1:10 5 superantigen polyclonal T cell response 1:4 - 1:10 Microbial proteins that bind to and activate all the T cells in an individual that express a particular set or family of TCR molecules 10 7 – 10 8 / 10 11 10 10 / 10 11 activated T cells SUPERANTIGENS

14. SUPERANTIGENS ClassificationSources Endogenous Exogenous B cell 1.Mouse mammary tomor virus (MMTV) 2.Epstein-Barr virus (EBV) 1.Staphylococcal enterotoxins (SEs): A, B, C1 to C3, D, E, G to Q 2.Staphylococcal toxic shock syndrome toxin-1 (TSST-1) 3.Staphylococcal exfoliative toxins: exoliatin A, exfoliatin B 4.Staphylococcal enterotoxin-like toxins formed due to recombination within enterotoxin gene cluster: U2, V 5.Streptococcal pyrogenic exotoxins (SPEs): A1 to A4, C, G to M 6.Streptococcal mitogenic exotoxins: SMEZ 7.Streptococcal superantigen :SSA 8.Yersinia pseudotuberculosis: Yersinia pseudotuberculosis-derived mitogen (YAM) 9.Mycoplasma species: Mycoplasma arthritidis-derived mitogen (MAM) 10.Cholera toxin: subunit A of cholera toxin 11.Prevotella intermedia* 12.Mycobacterium tuberculosis* 13.Viral superantigens: (a) Mouse leukemia virus (b) IDDMK1222- Ppol-ENV-U3 (c) HIV-Nef (d) Rabies virus-nucleoside protein 1.Staphylococcal protein A 2.Protein Fv (PFv).

15. T CELL-DEPENDENT B CELL ACTIVATION Polysacharides are not presented! B cell cytokines CD4 TCR MHCII +peptide T cell 2 1

16. T-INDEPENDENT ANTIGEN TI-1 T-INDEPENDENT ANTIGEN TI-2 crosslinking of BCR Strong crosslinking of BCR by repetitive polysaccharide or protein epitopes BCR and other receptors Simultaneous activation of BCR and other receptors on B cells (i.e. LPS binding protein /CD14) induces the B cells to proliferate and differentiate B cell B CELL ACTIVATION (extensive receptor-aggregation)(extra activation signal) B CELL ACTIVATION WITHOUT THE HELP OF T CELLS

18. Microorganisms have several different cell surface epitopes

19. Haptenic/antigen determinant (epitope) part of the antigen which are recognized by a defined immunoglobulin (B cell receptor or antibody) or by T cell receptor COMPLEX ANTIGENS CONSIST OF THE CARRIER AND MULTIPLE EPITOPES (=ANTIGEN DETERMINANTS) Carrier part of the antigen directly not involved in connection with the defined Ig/BCR or TCR These terms can only be used to describe the interaction of particular antigenic determinant and single immunoglobulin or T cell receptor HAPTEN substance that is non-immunogenic but which can react with the products of a specific immune response. Haptens are small molecules which could never induce an immune response when administered by themselves but which can when coupled to a carrier molecule. Free haptens, however, can react with products of the immune response after such products have been elicited. Haptens have the property of antigenicity but not immunogenicity.

20. carrier + hapten Small chemical structures that cannot induce B cell response on their own (e.g. drugs, reactive compounds) hapten (i.e. DNP:dinitrophenyl) - + HAPTENS hapten + 1. 2. primed

21. carrier specifichapten specificcarrier + hapten specific carrier + hapten antibodies Antibody response generated against a hapten- carrier conjugate

22. INTERACTION BETWEEN MICROORGANISMS AND THE IMMUNE SYSTEM

23. Symbiotic, non-pathogenic microbes – mucosal membrane, skin Bacteria, Fungi, Protozoa Gut – colonalization after birth 10 12 bacteria/g intestinal content 1000 species 100-times more bacterial genes than eukaryotic - „peaceful” commensalisms - vitamins (i.e. K1 vitamin) - real ecosystem, survival of the fittest, competition with pathogenic organism - the few who brake in through the gut epithelium induce local immune response Patogens Bacteria, Fungi, Protozoa, Viruses Helmints COMPLEX ANTIGENS Strong immunogens ANTIGENIC PROPERTIES OF PATHOGENIC AND NON-PATHOGENIC ORGANISMS

24. Important role in: - development of mucosal and systemic immunity - normal development of peripheral lymphoid organs - maintenance of basic level of immunity HEALTHY MICROFLORA IS REQUIRED FOR PROPER DEVELOPMENT OF THE IMMUNE SYSTEM

25. ACUTE INFLAMMATION AND ACUTE-PHASE RESPONSE

27. THE SKIN AND MUCOSAL EPITHELIUM AS INNATE BARRIERS

28. THE INFLAMMATORY RESPONSE

30. ACUTE INFLAMMATION Acute inflammation is a rapid response to an injurious agent that serves to deliver mediators of host defense — leukocytes and plasma proteins — to the site of injury. Acute inflammation has three major components: 1)alterations in vascular caliber that lead to an increase in blood flow 2)structural changes in the microvasculature that permit plasma proteins and leukocytes to leave the circulation 3)emigration of the leukocytes from the micro-circulation, their accumulation in the focus of injury, and their activation to eliminate the offending agent

31. ACUTE INFLAMMATORY REACTIONS ARE TRIGGERED BY A VARIETY OF STIMULI: Infections (pathogenic microbes and microbial toxins) Trauma (blunt and penetrating) Physical and chemical agents (thermal injury e.g. burns or frostbite; irradiation; some environmental chemicals) Tissue necrosis (from any cause) Foreign bodies (splinters, dirt, sutures) Immune reactions (hypersensitivity and autoimmune reactions)

32. The classic symptoms of inflammation: redness (rubor), swelling (tumor), heat (calor), pain (dolor), loss of function (functio laesa)

33. CHEMICAL MEDIATORS OF INFLAMMATION I. Vasodilation –prostaglandins, nitric oxide Increased vascular permeability –vasoactive amines (histamine, serotonin), C3a and C5a, bradykinin, leukotrienes, PAF Chemotaxic leukocyte activation –C3a, C5a, LTB 4, chemokines

34. CHEMICAL MEDIATORS OF INFLAMMATION II. Fever –IL-1, IL-6, TNF, prostaglandins Pain –prostaglandins, bradykinin Tissue damage –neutrophil and macrophage products lysosomal enzymes oxygen metabolites nitric oxide (NO)

35. MIGRATION OF NEUTROPHILS FROM BLOOD TO INFLAMMED TISSUE

36. MIGRATION OF NEUTROPHILS

37. Neutrophil Transendothelial Migration (Diapedesis)

38. ENDOTHELIAL ADHESION MOLECULES DURING INFLAMMATION

39. Pus is a whitish-yellow, yellow, or yellow-brown exudate produced by vertebrates during inflammatory pyogenic bacterial infections. Pus consists of a thin, protein-rich fluid, known as liquor puris, and dead cells. PUS

40. CONSEQUENCES OF MACROPHAGE ACTIVATION SYNTHESIS OF CYTOKINES

41. ACUTE-PHASE REACTION

42. ACUTE-PHASE RESPONSE

43. Liver Mannose binding lectin/protein MBL/MBP Fibrinogen Serum amyloid protein (SAP) C-reactive protein (CRP) UNDER THE INFLUENCE OF IL-6 THE LIVER PRODUCES A BUNCH OF ACUTE-PHASE PROTEINS Complement IL-6 ACUTE PHASE REACTION

44. RESOLUTION OF ACUTE INFLAMMATION

45. SEPTIC SHOCK Triggering factors : systemic infection (bacteraemia) microbial cell wall products and/or toxins released from the pathogens Result: Systemic activation of neutrophils and macrophages  High level of cytokine (TNF-alpha) production : „cytokine storm”  Excessive inflammatory response

46. SEPTIC SHOCK The key molecule of the process: TNF-alpha TNF-alpha and other inflammatory cytokines capillar permeability blood pressure DIC high fever multiorgan failure Therapy: anti-TNF-alpha antibody disseminated intravascular coagulation

47. DIC Disseminated Intravascular Coagulation pathologic activation of thrombotic process distress of thrombotic process, bleeding other causes: snake bite, septic abortion, acute obstetric complications, malignant tumors, leukemias

48. DIC: Disseminated Intravascular Coagulation