what is major histocompatibility complex
Definition of MAJOR HISTOCOMPATIBILITY COMPLEX. : a group of genes in mammals that code for cell-surface polymorphic glycoprotein molecules which display antigenic peptide fragments for T cell recognition and aid in the ability of the immune system to determine self from nonself. ADVERTISEMENT.edical Definition of MAJOR HISTOCOMPATIBILITY COMPLEX. : a group of genes in mammals that function especially in determining the histocompatibility antigens found on cell surfaces and that in humans comprise the alleles occurring at four loci on the short arm of chromosome 6âabbreviation MHC.