1. Physiological regulation of the immune system

2. Regulation by antigen Induce immune responses and extinction
Affinity maturation of B lymphocytes
Maintaining immunological memory
Antigenic competition
Threshold density of the complex MHC II-gp Ag on APC

3. Regulation by antibodies
Antibodies competes with the BCR for antigen (negative regulator of B lymphocyte stimulating)
IgG immune complexes bind to the BCR and FcgR on B cells, resulting in blocking activation of B lymphocytes
It is still unclear meaning of regulation via idiotypic network

4. Regulation by cytokines and cellular contact
Interaction APC - T lymphocyte
Interaction TH1 – macrophages
Interaction TH2 - B lymphocytes
Mutual regulation of activity TH1 versus TH2
Development of leukocyte subpopulations Negative regulation of effector cells:
CTLA-4 - T cell inhibitory receptor, binds ligands CD80 and CD86
Inhibitory receptors of NK cells
Self-destruction interaction of the apoptotic receptor Fas with ligand FasL on the surface of activated T lymphocytes

5. Factors influencing the outcome of the immune response
The same antigen can induce an active immune response or an active state of tolerance, the result of response depends on many factors:
State of the immune system
Properties of antigen
Dose of antigen
Route of antigen administration

6. Cytokines (Tissue hormones)

7. Cytokines
Regulatory proteins and glycoproteins produced by leukocytes and other cells
Essential regulators of the immune system
Apply outside the immune system (angiogenesis, tissue regeneration, carcinogenesis, treatment of many brain functions, embryonic development ...)
Cytokines - secreted      membrane (CD 80, CD86, CD40L, FasL ..)

8. Pleiotropic effect
Operates in a cascade
Cytokine Network
Cytokine system is redundant
Effects of cytokines - autocrine paracrine endocrine
Are known as interleukins (exception: TNF, lymphotoxin, TGF, interferons, CSF and growth factors)

9. B cells communicate via cytokines with other inflammatory cells, such as T cells and macrophages

10. Distribution of cytokines by function
Proinflammatory cytokines (IL-1, IL-6,IL- 8,IL- 12,IL- 18, TNF)
Antiinflammatory cytokines (IL-1Ra, IL-4, IL-10, TGF)
Cytokines with the activity of hematopoietic cells growth factor (IL-2, 3, 4, 5, 6, 7, 9, 11, 14, 15, CSF, SCF, LIF, EPO)
Cytokines applying in TH2 humoral immunity (IL-4, 5, 9, 13)
Cytokines applying in the cell-mediated immunity TH1 (IL-2, 12, IFN, GM-CSF, lymphotoxin)
Cytokines with anti-virus effect (IFN-, IFN-, IFN- )

11. Overview of the most important cytokines
Produced
Function
IL-1
MF, N
T cell costimulation, induction of TNF and IL-8, pyrogen
IL-2
Th1
Growth factor for T cells
IL-4
Th2, basophils
Th2 differentiation, B cell stimulation, isotype switching to IgE and IgG4, Th1 inhibition
IL-5
Th2, eosinophils
B cell stimulation, growth factor for eosinophils
IL-6
Th2, MF, N
T and B cell stimulation, stimulation of Ig production, induction of acute phase proteins synthesis, pyrogen
IL-8
MF, other cells
Granulocyte activation and chemotaxis (primarily neutrophils)
IL-10
Th2,M, Treg
Th1 and MF inhibition, B cell differentiation to plasma cell
IL-12
MF, DC, B
Th1 differentiation, NK stimulation
TNF
M, MF, NK
Induction of local inflammation, endothelium activation, induction of apoptosis
TGFb
T, MF, platelets
The anti-inflammatory effect (control of lymphocyte proliferation, control of Ig production, control MF activity), stimulation of fibroblasts and osteoblasts, gain production of extracellular matrix
IFNa
L, M, MF
Inhibition of viral replication
IFNb
Fibroblasts, epithelial cells
IFNg
Th1, NK
MF activation, stimulation of MHC gp. expression, Th2 inhibition
MF – macrophages; M – monocytes; N – neutrophils; DC – dendritic cells; NK – natural killers; L – lymphocytes; B – B cell; T – T cell

12. Cytokine receptors Consisting of 2 or 3 subunits
One subunit binds cytokine, other are associated with cytoplasmic signaling molecules (protein kinases)
Signaling subunit is shared by several different cytokine receptors - called receptor family
Signaling through these receptors may lead to proliferation, differentiation, activation of effector mechanisms or blocking the cell cycle and induction of apoptosis

13. External regulation of immune response

14. Substitution treatment
treatment with intravenous immunoglobulin (derived from plasma of blood donors)
substitution of C1 inhibitor for hereditary angioedema
substitution of erythropoietin in patients with chronic renal failure
substitution of G-CSF in agranulocytosis

15. Non-specific immunosuppressive therapy
Immunomodulation
= medical procedure to adjust the disrupted immune function
Non-specific immunosuppressive therapy
nonspecific = affects not only autoreactive and aloreactive                        lymphocytes, but also other components of immunity (risk of reduction antiinfectious and anti tumor immunity)
used for treatment of autoimmune diseases, severe allergic conditions and for organ transplantation

16. Non-specific immunosuppressive therapy
corticosteroids - anti-inflammatory, immunosuppressive effects                    blocking the activity of transcription factors (AP-1, NFkB)                    suppress the expression of genes (IL-2, IL-1, phospholipase A, MHC gp II, adhesion molecules)                   inhibition of histamine release from basophils                    higher concentrations induce apoptosis of lymfocytes
immunosuppressants affecting the metabolism of DNA - cyclophosphamide, azathioprine,methotrexate

17. immunosuppressant selectively inhibiting T lymphocytes
immunosuppressant selectively inhibiting T lymphocytes - immunosuppressive ATB: cyclosporine A, tacrolimus, rapamycin (suppressing the expression of IL-2 and IL-2R in activated T lymphocytes)                 - monoclonal antibody anti-CD3 (Immunosuppression after transplantation, treatment of rejection crises)
immunoglobulins in the immunosuppressive indication                  - Polyspecific intravenous immunoglobulins                    (Inhibition of B lymphocytes, antiidiotype activity, inhibition of cytokines, neutralization of toxins, inhibition of complement activation ...)

18. Anti-inflammatory and antiallergic treatment
nonsteroidal anti-inflammatory drugs
antihistamines - blocking H1 receptor                          - reduce the expression of adhesion molecules                          - reduce the secretion of histamine ...
inhibitors of inflammatory cytokine receptor antagonist for IL-1                          - monoclonal antibodies against TNF                          - thalidomide (TNF inhibitor)
enzyme therapy - in the enzyme mixture has a major effect trypsin and bromelain                            - anti-inflammatory and immunomodulatory effects

19. Non-specific immunostimulant therapy
synthetic immunomodulators
Methisoprinol (Isoprinosine) - used in viral infections with more severe or relapsing course
bacterial extracts and lysates
Broncho-Vaxom - prevention of recurrent respiratory tract infections
Ribomunyl
products of the immune system
IL-2 - renal adenocarcinoma
IFNa, IFNb - viral hepatitis, some leukemia
Erythropoietin – renal failure
G-CSF, GM-CSF – neutropenia
Transfer factor (blood donors leukocytes undergoing dialysis)
Thymus hormones               

20. Antigen-specific immunomodulatory therapy
specific immunomodulation = induce an immune response or tolerance against a specific antigen a) active immunization
b) passive immunization
c) specific immunosuppression
d) vaccination against cancer

21. a) active immunization = use of antigen to induce an immune response that can later protect against a pathogen bearing the antigen (or similar antigen)
immunization vaccines are made from inactivated or attenuated microorganisms or their antigens (polysaccharide capsule, toxins)
creates long-term immunity
activate cellular and antibody immunity
administration of antigen injectable, oral
prophylaxis
risk of causing infection or anaphylactic reactions

22. b) passive immunization
natural - transfer of maternal antibodies in fetal blood
therapeutically - the use of animal antibodies against various toxins (snake toxins, tetanus toxin, botulinum toxin)
prophylaxis - the human immunoglobulin from immunized individuals (hepatitis A, rabies, tetanus)                     - Anti-RhD antibodies - preventing maternal immunization with RhD+ fetus
provides a temporary (3 weeks) specific humoral immunity
the risk of induction anaphylactic reactions

23. c) specific immunosuppression = induction of tolerance against a specific antigen
ongoing clinical studies
induction of tolerance by oral administration of antigen (treatment of certain autoimmune diseases)
allergen immunotherapy (pollen, insect poisons)
d) vaccination against cancer
s a promising approach appears to immunization dendritic cells

24. Defense against extracellular pathogens

25. Defence against extracellular pathogens
bacteria (gram-negative, gram-positive cocci, bacilli), unicellular parasites
complement activation stimulated by bacterial cell wall
phagocytosis by neutrophil granulocytes
opsonization (C3b, lectins, antibodies ...) enhance phagocytosis

26. Opsonisation

27. Phagocytes are attracted to the site of infection by chemotactic substances (C5a, C3a and chemotactic products of bacteria)
absorbed bacteria are destroyed by the microbicidal systems (products of NADP-H oxidase, hydrolytic enzymes and bactericidal substances in lysosomes)
phagocytes produce proinflammatory cytokines (IL-1, IL-6, TNF) that induce an increase in temperature, metabolic response of the organism and synthesis of acute phase proteins

28. Phagocytosis

29. in later stages of infection are stimulated antigen-specific mechanisms
plasma cells initially produce IgM isotype after isotype switching produce IgG1 and IgA (opsonization)
sIgA protect against intestinal and respiratory infections by bacteria
bacteria with a polysaccharide capsule may cause T-independent IgM antibody production (after the establishment to the bacteria activate the classical complement path)

30. after infection persist IgG, IgA (protective effect) and memory T and B lymphocytes
in the defense against bacterial toxins apply neutralizing antibodies (Clostridium tetani and botulinum ...)
"indirect toxins - bacterial Lipopolysaccharide (LPS) stimulates big number of monocytes to release TNF, which can cause septic shock
extracellular bacterial infections are especially at risk individuals with disorders in the function of phagocytes, complement and antibody production

32. Defense against intracellular pathogens

33. Defense against intracellular pathogens
bacteria, fungi and unicellular parasites
intracellular parasites are resistant to the microbicidal mechanisms of phagocytes
macrophages, which absorbed them, produce IL-12 → TH1 differentiation, production of IFNg and membrane TNF → activation of macrophages and induction of iNOS

34. Obrana proti intracelulárním patogenům

35. in the defense against intracelular parasites, which escape from phagolysosomes apply TC lymphocytes
intracellular microorganisms infections are at risk individuals with certain disorders of phagocytes and defects of T lymphocytes

36. Defense against intracellular pathogens

37. Anti-viral defense

38. Anti-viral defence
interferons - in infected cells is induced production of IFNa and IFNb (prevents viral replication and in uninfected cells cause the anti-virus status); IFNg stimulates the conversion to activated macrophages (iNOS)
IFNa and IFNb induce proliferation of NK cells

39. Anti-viral defence - interferons

40. NK cells - ADCC (Antibody-dependent cell-mediated cytotoxicity) = cytotoxic reaction depends on the antibodies; the NK-lymphocyte recognizes cell opsonized with IgG by stimulation Fc receptor CD16 and then activate cytotoxic mechanisms (degranulation)
infected macrophages produce IL-12 (a strong activator of NK cells)

41. NK cell activation

42. in the defense against cytopathic viruses mostly applied antibodies:
sIgA inhibit mucosal adhesion of viruses (defense against respiratory viruses and enteroviruses)
neutralizing IgG and IgM antibodies activate the classical way of complement, which is capable of some viruses lysis
IgA and IgG derived in viral infection have a preventive effect in secondary infection

43. Anti-viral defence - antibodies

44. effector TC lymphocytes destroy infected cells in direct contact (granzym/perforin; FasL) and by produced cytokines (lymfotoxin)
some viruses after infection integrate into the host genome, where persist for years (varicella zoster, EBV, papillomavirus)
by these infections are at risk individuals with T lymphocyte immunodeficiency and with combined immune disorders
increased susceptibility to herpes infections in individuals with dysfunction of NK cells

45. Anti-viral defence – NK cells and Tc lymphocytes

46. Defense against multicellular parasites

47. Defense against multicellular parasites
IgE, mast cells, basophils and eosinophils
TH2 stimulation under the influence of IL-4 (mast cells and other APC stimulated by parasite)
TH2 stimulate B cells with BCR-specific parasite antigens
isotype switching under the influence of IL-4 to IgE
IgE bind to FceRI on mast cells and basophils („antigen-specific receptors“)

48. Mast cell activation
establish of multivalent antigen (multicellular parasite) using the IgE to highafinity Fc receptor for IgE (FcRI) aggregation of several molecules FcRI
initiate mast cell degranulation (cytoplasmic granules mergers with the surface membrane and release their contents)
activation of arachidonic acid metabolism (leukotriene C4, prostaglandin PGD2) - amplification of inflammatory responses
cytokine production by mast cell (TNF, TGF, IL-4, 5,6 ...)

49. Activation of mast cell

50. in later stages are activated TH1 and are produced antibodies of other classes
eosinophils fagocyte complexes of parasitic particles with IgE via their receptors for IgE
eosinophils use against parasites extracellular bactericidal substances released from granules (eosinophil cationic protein, protease)

51. Defense against multicellular parasites - eosinophils

52. Thank you for your attention