Chapter 9 - Immunological Tolerance and Autoimmunity Flashcards
what recognizes self antigens
lymphocyte receptors generated during T and B cell development
a healthy immune system is able to discriminate between ______
self and nonself antigens
what results in autoimmunity
failure to prevent a response to self antigens
only mount a full immune response to____
nonself antigens and non-commensal microbes
a healthy immune system is able to discriminate _____- from _______
commensal; non-commensal microbes
failure to prevent a response to commensal microbes results in ______
chronic inflammation
particular antigens will result in an ________ or ________
immunogenic response; tolerogenic response
what are the principle mechanisms of central T lymphocyte tolerance
- negative selection: deletion of CD4+ and CD8+
- Development of regulatory T cells (CD4+ T cells)
what are the principle mechansims of T lymphocyte tolerance
-T cell response to microbes and vaccines
- anergy
- suppression
-deletion
what happens in anergy
-functional unresponsiveness
- TCR does not send activating signal
- T cell engages an inhibitory receptor
what inhibitory receptors does T cell use in T cell anergy
CTLA-4: block and remove B7 costimulator from APCs
PD-1: inhibits signaling within cell
is APC stimulated by innate immunity
no
APCs express low amounts of _____
costimulators
what happens in suppression
regulatory T cells develop in the thymus or peripheral tissues on recognition of self antigens and suppress the activation of lymphocytes that also recognize these self antigens
how do regulatory T cells suppress immune responses
-cytokine signaling: inhibits activation of target cells
- CLTA-4 expression: remove B7 from APCs
- high amount of IL-2 receptor: depletes IL-2 in local area
