Final answer:
MHC II molecules are transmembrane glycoproteins that are expressed on the surface of antigen-presenting cells. They play a crucial role in the immune response by presenting processed foreign antigens to helper T cells. HLA-DM is a protein that helps ensure that only high-affinity peptides are presented to T cells by displacing weakly bound peptides from the antigen-binding cleft of MHC II molecules.
Step-by-step explanation:
MHC II molecules are transmembrane glycoproteins that are expressed on the surface of antigen-presenting cells (APCs) such as macrophages, dendritic cells, and B cells. They play a crucial role in the immune response by presenting processed foreign antigens to helper T cells.
HLA-DM, a protein involved in antigen processing, displaces weakly bound peptides from the antigen-binding cleft of MHC II molecules. This helps to ensure that only high-affinity peptides are presented to T cells, optimizing the immune response against pathogens and facilitating proper recognition of antigens.