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Antigen recognition in adaptive immunity

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Presentation on theme: "Antigen recognition in adaptive immunity"— Presentation transcript:

1 Antigen recognition in adaptive immunity
Mechanism of diversity of antigen receptors Maturation and selection of B lymphocytes Maturation and selection of T lymphocytes

2

3 Cells display several types of receptor and each of them is specific for a certain ligand
Cells within one clone display only one type of receptor specific for a certain ligand

4 Antigen receptors on lymphocytes
B cell T cell Antigens: proteins, polysaccharides, lipids, nucleic acids, small molecules Conformational and linear epitops Complex of peptide-MHC molecule on an APC Linear epitops

5 N N N N C C C C

6 k l a (a1 a2) g (g1 g2 g3 g4) d e m IgA(1,2) IgG(1,2,3,4) IgD IgE IgM
VH VH VL VL CDR1 CDR2 CDR3 k l CL CL Isotype a (a1 a2) g (g1 g2 g3 g4) d e m IgA(1,2) IgG(1,2,3,4) V (variable) region VL i VH IgD CH CH C (constant) region CL i CH IgE IgM

7 Antibodies structure function

8 T-cell receptor for antigen (TCR)
structure

9

10 Lymphocyte maturation

11 The Nobel Prize in Physiology or Medicine
1987 "for his discovery of the genetic principle for generation of antibody diversity" Susumu Tonegawa

12 Inherited configuration of gene loci for antigen receptors

13 Inherited configuration of gene loci for antigen receptors

14 Recombination and expression of immunoglobulin genes

15 Mechanisms of creation of antigen receptor diversity
~100 54 67 27 Mechanisms of creation of antigen receptor diversity 61 4

16 Every day 109 lymphocytes with 107 various specificities are generated (young)

17 Phases of B-cell maturation and selection

18 Phases of B-cell maturation and selection

19 Phases of B-cell maturation and selection

20 Phases of B-cell maturation and selection

21 Phases of B-cell maturation and selection

22 T-cell maturation in thymus

23 T-cell maturation in thymus

24 Faze u sazrevanju i selekciji T-limfocita

25 1. TCR gene recombination a. eliminates auto-reactive lymphocytes 2. Negative selection b. proteins, polysaccharides, lipids 3. TCR recognizes c. a and b, or g and d chains 4. Immunoglobulin gene recombination d. peptides within MHC molecule 5. TCR consists of e. constant region of heavy chains 6. Antibody has f. variable regions of heavy and light chains 7. Different isotypes have the same g. occurs only in thymus 8. Positive selection h. provides antibody diversity 9. Antibody can recognize i. two identical heavy and two identical light chains 10. Receptors of different clones of B cells have different j. enables survival of useful lymphocytes 1.____ g 2.____ a 3.____ d 4.____ h 5.____ c 6.____ i 7.____ e 8.____ j 9.____ b 10.____ f


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