Regulation of immune response Flashcards
tolerance
lack response to an antigen
three mechanisms of tolerance for T cells
- eliminate reactive cell populations
- neutralize reactive cell populations
- generate unique cell populations which can produce antigen-specific tolerance
role of thymus in T cell negative selection
expresses tissue-specific proteins
major process of eliminating auto-reactive T cells as they develop in the thymus; programmed cell death
clonal deletion
if T cells make it out of the thymus but then are found to be auto-reactive, what happens
clonal anergy
what structures perform negative selection of aB T cells in thymus
macrophages, dendritic cells
process that gets rid of 99% of T cells
central tolerance
AIRE
autoimmune regulator
if a naive T cell recognizes self antigen on an epithelial cell, is a coreceptor necessary to induce anergy?
no
functional deletion of T cells
produce Tregs
Tregs
react with same cell as auto-reactive T cell
-suppress autoimmune response
FoxP3
txn factor for Tregs
what cytokine induces differentiation of Tregs
TGF-beta
FoxP3+, CD25+, CD4+ T cells
Tregs
how are Tregs selected
in thymus on MHC Class II
mutation in FoxP3
IPEX = autoimmune (enteropathy, diabetes, thyroiditis, eczema)
turns off T cells
CTLA-4
CTLA-4 antibody causes
persistent activation of T cells
Is there AIRE in bone marrow? what does this mean
- no –> B cells are more likely than T cells to be self reacting
- need T cells, or TLR to respond
do rearrangements occur after a B cell has Ig status?
yes
-light chain can still be rearranged once IhM is present
mechanisms of tolerance for B cells
clonal deletion, clonal anergy, functional deletion
how is the developmental environment different for B and T cells
thymus educates, bone marrow not as much
weak immunogen
requires less stringent regime for induction of tolerance
what kind of drugs generate self tolerance
immunosuppressants
