A Nonfunctional CD4 Protein on a Helper T Cell Would

Question

A nonfunctional CD4 protein on a helper T cell would result in the helper T cell being unable to
A)respond to T-independent antigens.
B)lyse tumour cells.
C)stimulate a cytotoxic T cell.
D)interact with a class I MHC-antigen complex.
E)interact with a class II MHC-antigen complex.

Accepted Answer

The CD4 protein on a helper T cell interacts with a class II MHC-antigen complex on an antigen-presenting cell (APC) to activate the helper T cell. Without a functional CD4 protein, the helper T cell would not be able to interact with the class II MHC-antigen complex and would therefore be unable to stimulate other immune cells.