Question

A mutation that renders the MHC class II molecule HLA-DM nonfunctional would likely lead to:

1) cells unable to synthetize MHC class II molecules.
2) cells with no HLA-DO.
3) cells with MHC class II molecules only bound with CLIP.
4) cells with class II MHC bound with a variety of self-antigens.
5) a deficiency in CD8+ T cells.

Answer 1

A nonfunctional HLA-DM would result in MHC class II molecules being bound only with CLIP, hindering the antigen presentation process and weakening the immune response.

Step-by-step explanation:

A mutation that renders the MHC class II molecule HLA-DM nonfunctional would likely lead to cells with MHC class II molecules only bound with CLIP. HLA-DM plays a critical role in the MHC class II antigen presentation pathway by facilitating the release of the invariant chain peptide, CLIP, from the MHC class II molecule. Without functional HLA-DM, CLIP cannot be efficiently released, preventing the binding of other peptides, including pathogen-derived antigens, to MHC class II. As a result, T cells cannot be effectively activated, compromising the immune response.