1. Tumor immunology

2. Tumor antigens Tumor – specific antigens (TSA)
complexes of MHCgp I with abnormal fragments of cellular proteins (chemically induced tumors, leukemia with chromosomal translocation)
complexes of MHC gp with fragments of oncogenic viruses proteins (tumors caused by viruses: EBV, SV40, polyomavirus…)
abnormal forms of glycoproteins (sialylation of surface proteins of tumor cells)
idiotypes of myeloma and lymphoma (clonotyping TCR and BCR)

3. Tumor antigens b) Tumor - associated antigens (TAA)
present also on normal cells
differences in quantity, time and local expression
auxiliary diagnostic markers

4. Tumor - associated antigens (TAA)
onkofetal antigens -on normal embryonic cells and some tumor cells
-fetoprotein (AFP) - hepatom
carcinoembryonic antigen (CEA) - colon cancer
melanoma antigens - MAGE-1, Melan-A

5. Tumor - associated antigens (TAA)
antigen HER2/neu eceptor for epithelial growth factor, mammary carcinoma
EPCAM – epithelial cell adhesion molecule, metastases
differentiation antigens of leukemic cells - present on normal cells of leukocytes linage
CALLA -acute lymphoblastic leukemia (CD10 pre-B cells)

6. Immune surveillance of tumors

7. Anti-tumor immune mechanisms
If tumor cells are detected, in defense may be involved non-specific mechanisms (neutrophilic granulocytes, macrophages, NK cells, complement) and antigen-specific mechanisms (TH1 and TC cells, antibodies).

8. Anti – tumor defense tumor cells are weakly immunogenic
regulatory T cells promote progression of cancer
occurs when tumor antigens are presented to T cells by dendritic cells activated in the inflammatory environment

9. Anti – tumor defense
DC are necessary for activation of antigen specific mechanisms
predominance of TH1 (IFN , TNF)
specific cell-mediated cytotoxic reactivity – TC
activation of TH2 → stimulation of B cells→ tumor specific antibodies production (involved in the ADCC)
tumor cells are destroyed by cytotoxic NK cells (ADCC)
interferons - antiproliferative, cytotoxic effect on tumor cells INF - DC maturation

10. Mechanisms of tumor resistance to the immune system
high variability of tumor cells
low expression of tumor antigens
sialylation
some anticancer substances have a stimulating effect
production of factors inactivating T lymphocytes
expression of FasL → T lymphocyte apoptosis
inhibition of the function or durability dendritic cells (NO, IL-10, TGF-)

11. Transplantation 11

12. Transplantation = transfer of tissue or organ
autologous - donor = recipient
syngeneic - genetically identical donor and recipient (identical twins)
allogeneic - genetically nonidentical donor of the same species
xenogenic - the donor of another species
implant - artificial tissue compensation 12

13. Allotransplantation
differences in donor-recipient MHC gp and secondary histocompatibility Ag
alloreactivity of T lymphocytes - the risk of rejection and graft-versus-host disease 13

14. Tests prior to transplantation
ABO compatibility (matching blood group) -risk of hyperacute or accelerated rejection (= formation of Ab against A or B Ag on graft vascular endothelium)
HLA typing (matching tissue type) - determining of HLA alelic forms by phenotyping or genotyping
Cross-match - detection of preformed alloantibodies
(after blood transfusions, transplantation, repeated childbirth)
Mixed lymphocyte reaction - testing of T lymphocytes alloreactivity 14

15. HLA typing
1) Serotyping (microlymfocytotoxic test)

16. HLA typing 2) Molecular genetic methods- genotyping 2a) PCR-SSP
2b) PCR-SSO
2c) PCR-SBT

17. Cross-match testing determination of preformed alloantibodies
recipient serum + donor lymphocytes + rabbit complement → if cytotoxic Ab against donor HLA Ag are present in recipient serum , Ab activate complement → lysis of donor lymphocytes Dye penetration into lysis cells.
positive test = the presence of preformed Ab → risk of hyperacute rejection! → contraindication to transplantation 17

18. FACS crossmatch
Mulley WR et al. Nephrology 16: , 2011

19. Mixed lymphocyte reaction (MLR)
Two – way MRL
determination of T lymphocytes alloreactivity
mixed donor and recipient lymphocytes → T lymphocytes after recognition of allogeneic MHC gp activate and proliferate
this assay was used to study possible donor - recipient incompatibilities for graft transplants to help predict better outcomes 19

20. One-way MRL
determination of recipient T lymphocytes reactivity against donor cells
donor cells treated with chemotherapy or irradiated lose the ability of proliferation

21. Rejection
hyperacute
accelerated
acute
chronic

22. Hyperacute rejection minutes to hours after transplantation
humoral mediated immune response
mechanism:
if in recipients blood are present preformed or natural Ab (IgM anti- carbohydrate Ag) before transplantation → Ab + Ag of graft (MHC gp or endothelial Ag) → graft damage by activated complement
the graft endothelium: activation of coagulation factors and platelets, formation thrombi, accumulation of neutrophil granulocytes
prevention:
negative cross match before transplantation, ABO compatibility 22

23. Accelerated rejection
3 to 5 days after transplantation
caused by antibodies that don´t activate complement
cytotoxic and inflammatory responses triggered by binding of antibodies to Fc-receptors on phagocytes and NK cells
prevention:
negative cross match before transplantation, ABO compatibility 23

24. Acute rejection
days to weeks after the transplantation or after a lack of immunosuppressive treatment
cell-mediated immune response
mechanism:
reaction of recipient TH1 and TC cells against Ag of graft tissue
infiltration by lymphocytes, monocytes, granulocytes around small vessels → destruction of tissue transplant 24

25. Chronic rejection from 2 months after transplantation
the most common cause of graft failure
mechanism is not fully understood:
non-immunological factors (tissue ischemia) and TH2 response with production alloantibodies, pathogenetic role of cytokines and growth factors (TGFβ)
fibrosis of the internal blood vessels of the transplanted tissue, endothelial damage →impaired perfusion of graft → gradual loss of its function
dominating findings: vascular damage 25

26. Rejection
Factors:
The genetic difference between donor and recipient, especially in the genes coding for MHC gp (HLA)
Type of tissue / organ - the strongest reactions against vascularized tissues containing many APC (skin)
The activity of the recipient immune system – the immunodeficiency recipient has a smaller rejection reaction; immunosuppressive therapy after transplantation – suppression of rejection
Status of transplanted organ - the length of ischemia, the method of preservation, traumatization of organ at collection 26

27. Graft-versus-host (GvH) disease
after bone marrow transplantation
GvH also after blood transfusion to immunodeficiency recipients
T-lymphocytes in the graft bone marrow recognize recipient tissue Ag as foreign (alloreactivity) 27

28. Acute GvH disease
days to weeks after the transplantation of stem cells
damage of liver, skin and intestinal mucosa
prevention: appropriate donor selection, the removal of T lymphocytes from the graft and effective immunosuppression

29. Chonic GvH disease months to years after transplantation
infiltration of tissues and organs by TH2 lymphocytes, production of alloantibodies and cytokines → fibrosis
process like autoimmune disease: vasculitis, scleroderma, sicca-syndrome
chronic inflammation of blood vessels, skin, internal organs and glands, which leads to fibrosis, blood circulation disorders and loss of function 29

30. Graft versus leukemia effect (GvL)
donor T lymphocytes react against residual leukemick cells of recipient (setpoint response)
mechanism is consistent with acute GvH
associated with a certain degree of GvH (adverse reactions) 30

31. Immunopathological (hypersensitivity) reactions31

32. Immunopathological reactions
Immune response which caused damage to the body (Consequence of immune response against pathogens, inappropriate responses to harmless antigens; autoimmunity)

33. Immunopathological reactions
Classification by Coombs and Gell
IV types of immunopathological reactions:
Type I reaction - response based on IgE antibodies
Type II reaction - response based on antibodies, IgG and IgM
Type III reaction - response based on the formation of immune complexes
Type IV reaction - cell-mediated response 33

34. Immunopathological reaction type II (cytotoxic hypersensitivity reactions)
Cytotoxic antibodies IgG and IgM bind to cell surface antigens on own cells:
complement activation
binding to Fc receptors on phagocytes and NK cells (ADCC) 34

35. Examples of immunopathological reaction type II
Transfusion reactions after administration of incompatibile blood: binding of antibodies to antigens on erythrocytes → activation of the classical pathway of complement → cell lysis
Hemolytic disease of newborns: caused by antibodies against RhD antigen

36. Examples of immunopathological reaction type II
Autoimmune diseases:
organ-specific cytotoxic antibodies (antibodies against erythrocytes, neutrophils, thrombocytes, glomerular basement membrane ...)
blocking or stimulating antibodies
Graves - Basedow's disease - stimulating antibodies against the receptor for TSH
Myasthenia gravis - blocking of acetylcholin receptor→ blocking of neuromuscular transmission
Pernicious anemia - blocking the absorption of vitamin B12
Antiphospholipid syndrome - antibodies against fosfolipids
Fertility disorder - antibodies against sperms or oocytes 36

37. Immunopathological reaction type III (immune-complex reactions)
circulating antigen- IgG antibody immune complexes that deposit in tissues
immunocomplexes - activate complement
- bind to Fc receptors on phagocytes
immune complexes, depending on the quantity and structure, are eliminated by phagocytes or stored in tissues 37

38. Immunopathological reactions type III
pathological immunocomplexes response arises when is a large dose of antigen, or antigen in the body remains; arise days after aplication of Ag and induced inflamation (can get to chronic state)
immune complexes are deposited in the kidneys (glomerulonephritis), on the surface of endothelial cells (vasculitis) and in synovie joint (arthritis)

39. clinical manifestations: urticaria, arthralgia, myalgia
Serum sickness
the therapeutic application of xenogeneic serum (antiserum to snake venom)
creation of immune complexes and their storage in the vessel walls of different organs
clinical manifestations: urticaria, arthralgia, myalgia
Systemic lupus erythematosus
antibodies against nuclear antigens, ANA, anti-dsDNA
Farmer's lung
IgG antibody against inhaled antigens (molds, hay)
Post-streptococcal glomerulonephritis, cryoglobulinemia, revmatoid arthritis, post-infectious arthritis 39

40. Immunopathological reaction type IV (delayed-type reaction - DTH)
local reaction caused by TH1 cells and monocytes/macrophages (physiologically –defense against intracellular pathogens)
immunization by antigen → formation of antigen specific TH1 cells and memory cells
12-48 hours after next antigen exposure arise local reaction → granuloma (TH1 and macrophage infiltration)
Tuberculin skin tes reaction
Tissue damage in tuberculosis and leprosy
Sarcoidosis
Multiple sclerosis 40

41. Subtype IV - Cellular cytotoxic response (Tc activation)
similar to DTH reaction
TH1 cells activate CD8 + T lymphocytes
viral rashes
 viral hepatitis
acute rejection of transplanted organ
some autoimmune thyroiditis
contact dermatitis

42. Contact dermatitis
is a localized rash or irritation of the skin caused by contact with alergen (nickel , chromium, ingredients in cosmetic products , plant allergens and other)
the first is senzitization
appears in 24 – 48 hours after second contact with alergen
diagnosis : patch test

43. Patch test
patch test is a method used to determine if a specific substance causes allergic inflamation of the skin
Allergens are applied to special hypoallergenic patch on the back skin
Results are evaluated after 48 and 72 hours
In positive reaction appears eczema

44. Thank you for your attention

45. Tumour immunology and immunotherapy
Q8zsg
This is how your immune system fights cancer
qFZV3o