Antigen recognition by t lymphocytes
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Transcript of Antigen recognition by t lymphocytes
Antigen recognition by T lymphocytes
Dr. Glorivee Rosario-Pérez
BIOL 4056
Parham P. (2009). The Immune System. Third Edition. Garland Publishing, New York.
T cell receptor diversity
T cell receptor vs ImmunoglobulinT cell receptor Immunoglobulin
Membrane-bound glycoprotein Membrane-bound glycoprotein
It is composed of two different chains and has one antigen-binding site.
It is composed of two different chains and has one antigen-binding site.
Always membrane bound
No secreted form
Membrane bound
Secreted form
Variable region (binds antigen)
Constant region
Variable region (binds antigen)
Constant region
During T cell development, gene rearrangement produces sequence variability in the variable regions of the T cell receptor.
During B cell development, gene rearrangement produces sequence variability in the variable regions of the immunoglobulin.
After the T cell is stimulated with antigen, there is no further mutation in the antigen-binding site and there is no switching of constant region isotype.
After the B cell is stimulated with antigen, occur mutation in the antigen-binding site and switching of constant region isotype.
T cell receptors are used only as receptors to recognize antigen
Immunoglobulin serve as both recognition and effector molecules
Figure 3-11
T cell receptor
Figure 4-11
Chromosome 14
Chromosome 7
T cell receptor
T cell receptor diversity
Figure 4-13
T cell receptor complex
Two classes of T cell receptors
Antigen processing and presentation
Antigen processing and presentation complejo de inmunocompatibilidad
T cell : CD4 and CD8
CD8
Are cytotoxic.
Their main function is to kill cells that have become infected with a virus or some other intracellular pathogen.
This response prevents the multiplication of the pathogen and further infection of healthy cells.
CD4
Help other cells of the immune system to respond to extracellular sources of infection.
Two subclasses: TH1 – activate tissue macrophages to
phagocytose and kill extracellular pathogens, and to secrete cytokines and other active molecules that affect the course of the immune response.
TH2 – involved mainly in stimulating B cells to make antibodies, which bind to extracellular bacteria and virus particles.
T cells function : CD4 and CD8
MHC
MHC class I and II
Figure 3-20
Figure 3-21
Figure 1-27
Figure 1-28
Figure 1-29 part 1 of 2
Figure 1-29 part 2 of 2
Figure 1-30
Figure 1-31 part 1 of 2
Figure 1-31 part 2 of 2
Peptides and MHC I / MHC II
Figure 5-2
Peptides and MHC I
Peptides and MHC I
Figure 5-3 part 1 of 2
Peptides and MHC I cont.
Peptides and MHC II
Figure 5-7
Peptides and MHC II cont.
Figure 5-8
Figure 5-10
MHC and cells
MHC complex
Human MHC I and II isotypes
Figure 5-13
Figure 4-25