When a CTL with FasL interacts with a target cell possessing Fas, what happens to the target cell?
A) The target cell dies via apoptotic cell death.
B) Nothing; the target cell is healthy and remains intact.
C) The target cell goes into cell cycle arrest and repairs damage.
D) Nothing, but the interaction with the target cell causes death of the CTL.

Question

Quizplus · Accepted Answer

The interaction with FasL on the T cell activates death domains on Fas of the target cell, leading to apoptotic cell death of the target cell, not the CTL. The CTL is not harmed by this interaction. However, if the CTL possessed Fas and the target cell expressed FasL, then the target cell could kill the T cell, and this is the case occasionally with tumor cells that express FasL as a protective mechanism against an immune response.

When a CTL with FasL Interacts with a Target Cell