antigen recognition in adaptive immunity
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Antigen recognition in adaptive immunity. Mechanism of diversity of antigen receptors Maturation and selection of B lymphocytes Maturation and selection of T lymphocytes. Cells display several types of receptor and each of them is specific for a certain ligand. - PowerPoint PPT PresentationTRANSCRIPT
Antigen recognition in adaptive immunity
Mechanism of diversity of antigen receptors
Maturation and selection of B lymphocytes
Maturation and selection of T lymphocytes
Cells within one clone display only one type of receptor specific for a
certain ligand
Cells display several types of receptor and
each of them is specific for a certain ligand
Antigen receptors on lymphocytes
Antigens: proteins, polysaccharides, lipids, nucleic acids, small molecules
Conformational and linear epitops
Complex of peptide-MHC moleculeon an APC
Linear epitops
Bcell
Tcell
C C
C C
N NN N
CH CH
CL CL
VHVHVLVL
IgA(1,2)
IgG(1,2,3,4)
IgD
IgE
IgM
CDR1
CDR2
CDR3CDR3
CDR2
CDR1
V (variable) regionVL i VH
C (constant) regionCL i CH
Isotype
Antibodies• structure• function
T-cell receptor for antigen (TCR)structure
Lymphocyte maturation
Susumu Tonegawa
"for his discovery of the genetic principle for generation of antibody diversity"
The Nobel Prize in Physiology or Medicine
1987
Inherited configuration of gene loci for antigen receptors
Nasleđena konfiguracija genskih lokusa za antigenske receptore
Recombination and expression of immunoglobulin genes
Mechanisms of creation of antigen receptor diversity
~100 54 67
27
461
Every day 109 lymphocytes with 107 various specificities are generated (young)
Phases of B-cell maturation and selection
Phases of B-cell maturation and selection
Phases of B-cell maturation and selection
Phases of B-cell maturation and selection
Phases of B-cell maturation and selection
T-cell maturation in thymus
T-cell maturation in thymus
Faze u sazrevanju i selekciji T-limfocita
enables survival of useful lymphocytesj.Receptors of different clones of B cells have different
10.
two identical heavy and two identical light chains
i.Antibody can recognize9.
provides antibody diversityh.Positive selection8.
occurs only in thymusg.Different isotypes have the same7.
variable regions of heavy and light chains
f.Antibody has6.
constant region of heavy chainse.TCR consists of5.
peptides within MHC moleculed.Immunoglobulin generecombination
4.
and or and chainsc.TCR recognizes3.
proteins, polysaccharides, lipidsb.Negative selection2.
eliminates auto-reactive lymphocytesa.TCR gene recombination1.
10.____9.____8.____7.____6.____5.____4.____3.____2.____1.____g a d h c i e j b f