Question

Fred, a college junior, wakes up one morning to find a cold sore has erupted on his lower lip overnight. As a biology major, Fred has learned this is a symptom of infection with herpes simplex virus. The lesion begins to heal in five days, demonstrating his CD8 cytotoxic T lymphocytes (CTL) have been activated to kill the virus-infected cells. What is the protein that is secreted by these lymphocytes which enters the infected cell through a specialized pore, then activates an enzyme pathway that culminates in apoptotic death of the target cell?

a. Granzyme B

b. TNF-alpha

c. IL-2

d. Fas ligand (FasL)

Answer 1

Correct option is d - FasL (Fas ligand).

Explanation: FasL binds to its specific receptor and initiates caspase 3 mediated apoptotic pathway which ultimate leads to cell death.