tolerance Flashcards
in the thymus, what do T cells mature into?
double positive cells
in order to live, DP cells must pass what two tests?
MHC restriction, and tolerance to self
(positive selection)
The maturing T cell must only recognize peptides presented on MHCs–(about 95% of the deaths)
MHC restriction
(negative selection)–The maturing T cell must not recognize self peptides–(about 2-5% of deaths)
Tolerance to self
what is the function of cortical epithelial cells?(CEC)
See if T cells recognize either MHC I or MHC II
what cells give tolerance for self(negative selection)
Thymic Dendritic Cells•Medullary Thymic Epithelial Cells
these express 1000’s of tissue specific proteins (antigens) that are unique to different tissues/organs in the body
Medullary thymic epithelial cells
T cells do recognize MHC-peptide complexes
positve selection
T cells do not recognize self antigens
negative selection, (thymic dendritic cells, M.T.E.C’s)
results from a relatively weak interaction between TCRs & MHC self peptide displayed on cortical thymicepithelial cells
positive selection
induced by a strong interaction between TCRs & MHC self peptide displayed on thymicdendritic cells or medullary thymicepithelial cell
negative selection
what are able to suppress activation of potentially self-reactive T cells via downregulation
nTregs
T cells that recognize abundant self antigen in thymus are killed
central tolerance
Potentially self reactive Naïve T cells don’t see abundant self antigen in tissues because they are restricted from those tissue
traffic patterns
nTregs•Suppress activation of potentially self reactive T cells
tolerance induction in secondary lymphoid organs
