MHC markers determine which antigens an individual can respond to, and how strongly.
Moreover, MHC markers allow immune cells such as B cells , T cells , and macrophages to recognize and communicate with one another. One group of proteins encoded by the genes of the MHC are the markers of self that appear on almost all body cells. A second group of MHC proteins, class II antigens, are found on B cells, macrophages, and other cells responsible for presenting foreign antigen to helper T cells. Class II products combine with particles of foreign antigen in a way that showcases the antigen and captures the attention of the helper T cell .