Question

After an infection, activated T cells are no longer needed, and cessation of the antigenic stimulus prompts them to undergo programmed cell death or apoptosis. One mechanism of apoptosis that has been well defined is the interaction of the receptor molecule Fas on T cells with its ligand FasL. The signaling activity leading to apoptosis begins with what receptor interacting molecule?

a) ICAM-1
b) FADD
c) Mac-1
d) LFA-1
e) VLA-4

Answer 1

FADD (Fas-associated death domain) is the apoptotic molecule that initiates the signaling leading to apoptosis in T cells through the interaction with the Fas receptor.

Step-by-step explanation:

The signaling activity leading to apoptosis in T cells through the Fas/FasL pathway begins with the interaction of the apoptotic molecule FADD (Fas-associated death domain) with the Fas receptor. When Fas on the T cell surface binds with its ligand FasL, which is expressed on cytotoxic T cells and NK cells, it recruits FADD.

This interaction triggers a cascade of events leading to apoptosis, effectively allowing the immune system to regulate the number of T cells and prevent autoimmunity.