The unity of genes in the Major histocompatibility complex

Abstract

The major histocompatibility complex (MHC) of the mouse can be genetically divided into several regions specialized to performing specific functions. Thus the class I regions (K and D ) code for antigens that activate effector (killer) T cells, class I1 region (I) for antigens causing T-cell proliferation, and class I11 regions ( 8 ) for complement components. A strong case is made for the theory that the division of labor within the MHC is not absolute. Evidence is presented that class I antigens can sometimes cause as strong T-cell proliferation as class I1 antigens; that class I1 antigens can generate effector T cells; and that class I antigens may be involved in the immune response to some antigens. The fact that different regions can perform similar functions argues for the unity of the MHC genes.