Question

During the adaptive response, the MHC molecules are responsible for presenting an antigen to T cells. The two types of MHC (MHCI and MHCII) have specific roles during the response. Which of the following most accurately describes the characteristics of MHCII molecules in mounting the antibody response?

a. found on all nucleated cells, present endogenous antigens, activate cytotoxic T cells
b. found on APC, present exogenous antigens, activate cytotoxic T cells
c. found on APC, present endogenous antigens, activate T helper cells
d. found on APC, present exogenous antigens, activate T helper cells

Answer 1

D

Step-by-step explanation:

MHC II molecules are only found on the APCs and will present any antigen brought in through a vesicle, aka an exogenous antigen.

It'll activate T helper cells to secrete cytokines that will activate macrophages if it's a Th1 cell, or B cells if it's a Th2 cell.

MHC I cells however are present on any nucleated cell and will present an endogenous antigen (usually a virus) to activate T cytotoxic cells. All our cells need MHC I because any of our cells can get infected by a virus.