Peptide editing is an important component of antigen presentation for both MHC class I and MHC class II pathways, as it drives the preferential presentation of high-affinity binding peptides. For MHC class II peptide editing, HLA-DM plays a key role. In the absence of HLA-DM:
A) MHC class II molecules traffic to the cell surface with CLIP in their binding sites.
B) No MHC class II molecules are released to traffic to the cell surface.
C) MHC class II molecules bind to HLA-DO and are inhibited from binding peptides.
D) Pathogens can evade the immune system by blocking peptide exchange on MHC class II.
E) HLA-DO competes for high-affinity binding peptides with MHC class II molecules and blocks antigen presentation.

Question

Quizplus · Accepted Answer

In the absence of HLA-DM, MHC class II molecules often traffic to the cell surface with CLIP (Class II-associated invariant chain peptide) still bound in their peptide-binding groove, because HLA-DM facilitates the release of CLIP and the binding of other peptides.

Peptide Editing Is an Important Component of Antigen Presentation for Both