Definition: Membrane glycoproteins consisting of an alpha subunit and a BETA 2-MICROGLOBULIN beta subunit. In humans, highly polymorphic genes on CHROMOSOME 6 encode the alpha subunits of class I antigens and play an important role in determining the serological specificity of the surface antigen. Class I antigens are found on most nucleated cells and are generally detected by their reactivity with alloantisera. These antigens are recognized during GRAFT REJECTION and restrict cell-mediated lysis of virus-infected cells.
Other names Class I Antigens; I Antigens, Class; Antigens, Class I; Human Class I Antigens; Class I Major Histocompatibility Antigens; Class I Human Antigens; Class I Histocompatibility Antigens