chapter 9 Flashcards
3 pathways when immature lymphocyte recognizes of self antigen in central tolerance (thymus and bone marrow)
apoptosis
change in receptors (b cells only)
development of regulatory t lymphocytes (CD4 t cells)
3 pathways in peripheral tolerance when recognition of self antigen occurs
anergy
apoptosis
supression
this mech of peripheral t lymphocyte tolerance, TCR does not send activating signals and the t cell engages an inhibitory receptor
(functional unresponsiveness)
anergy
this response in peripheral tissue on recognition of self antigens and suppress (inhibits) the activation of lymphocytes that also reognizes these self antigens
suppression
regulatory t-cells suppress immune responses by
- cytokine signaling (inhibits activation of target cells)
- CTLA-4 expression (removes B7 from APCs)
- high amounts of IL-2 receptor (depletes IL-2 in local area)
3 principle mechanisms of central B lymphocyte tolerance (which are activated by t cells)
- non-self reactive b cell (receptor editing: expression of new IgV region)
- deletion (apoptosis)
- anergic b cell (reduced receptor expression, signaling)
unresponsiveness of the immune system to self antigens
immunologic tolerance