large transmembrane non-covalently linked glycoproteins; class II antigens in humans are called HLA-D antigens and coded on a gene on chromosome 6; in mice two genes named IA and iE on chromosome 17 code for the H-2 antigens; class II antigens are found on B-lymphocytes, macrophages, epidermal cells and sperm and are thought to mediate the competence of and cellular cooperation in the immune response.
