The adaptive immune system has mechanisms of homeostasis that serve to terminate immune responses and return the immune system to a basal resting state.Which of the following is LEAST likely to be involved in lymphocyte homeostasis?
A)CTLA-4
B)Fas ligand
C)CD28
D)B cell Ig Fc receptors
E)Anti-idiotypic antibodies

Question

Quizplus · Accepted Answer

CD28 binds to B7-1 or B7-2 and provides activating signals to T cells during the initiation of T cell responses,not self-regulating signals during the waning of an immune response.Although mechanisms of homeostasis in normal immune responses to foreign antigens are not well defined,they may include the same mechanisms that are important for self-tolerance,such as CTLA-4-mediated T cell inhibition and Fas-Fas ligand-mediated lymphocyte apoptosis.B cell homeostasis is mediated in part by antibody feedback inhibition,via FcF1F1F1S1F1F1F10RIIB,and by anti-idiotypic antibodies that are induced during immune responses and are specific for the unique antigen-binding regions of other antibodies.

The Adaptive Immune System Has Mechanisms of Homeostasis That Serve