immune response Flashcards
exam 4
must be turned down when antigen has been destroyed
immune response
failure to control the immune response
autoimmune disease
CTLA-4 competes with CD28
B7
activated T cells develop Fas ligand that reacts with Fas normally present on T cells leading to apoptosis of that cell
activation induced cell death
inhibit all T cell function
Cytokines IL-10 and TGfB
Treg makes
Cytokines IL-10 and TGfB
lack of response to a specific antigen
immunologic tolerance
failure to induce specific immunity to that antigen
immunologic tolerance
unresponsive to SELF antigens
self-tolerance
self- tolerance occurs in the thymus (negative selection),
central tolerance
cells that escape the central tolerance are dealt by
peripheral tolerance
continuous exposure to self-Ag’s causes continuous stimulation of T cells causing apoptosis of autoreactive lymphocytes. this occurs by the process of activation-induced cell death (Fas-FasL)
clonal deletion
absence of co-stimulatory signals especially B7-CD28
clonal anergy
peripheral tolerance mechanism [2]
- clonal deletion
2. clonal anergy
recipient will be born tolerant to black mouse antigens and will not reject the graft when skin from black mouse is transplanted to a white mouse in utero
fetal tolerance
Adult tolerance is very difficult to induce?
yes
failure of negative slection in the thymus
auto-immune
failure of immunological control mechanism
auto-immune
exposure of hidden antigens
factor that could give rise to autoimmune
sympathetic opthalamia
exposure of hidden antigens
polyclonal lymphocyte activation
factor that give rise to auto-immunity
viruses such as EBV stimulate B cells and non-specifically
polyclonal lymphocyte activation
superantigens stimulate T-cells
polyclonal lymphocyte activation
attach to the outside of the T cell receptor and to the MHC II molecules causing T cell activation
superantigen