Question

After the CTL (cytotoxic T cell) binds to the correct presented antigen, the target cell is killed via the ____________ and __________pathways.

perforin, lecithin

alternative, CD95

perforin/granzyme, CD95

ROS, lecithin

classical; lecithin

perforin, CD8

Answer 1

Answer:- (c) perforin/granzymes , CD95

Explanation:- the principal mechanism of T-cell mediating killing of presented antigen involves granzymes and perforins. These mediators are present in the lysosomes like granules of cytotoxic T cells. CTLs recognise the antigens and secrete a complex containing of perforins, granzymes and other proteins that enters target cells by endocytosis. In antigen cell cytoplasm, perforins facilitate the release of granzymes from the complex. Granzymes are proteases that cleave and activate the caspases which induce apoptosis of target cells.

Activated CTLs also express Fas ligand (FasL) , to which death receptor protein called Fas( CD95) get attached and extrinsic pathway (CD95) pathway of apoptosis occurs. And the presented antigen get killed.