Immunological Surveillance: T Cell Repertoire and the Biological Function of MHC Antigens

Abstract

Ten years ago we had no clear idea of the biological role of the major histocompatibility complex (MHC), though many people were trying to deal with the issue intellectually.1–4 The phenomenon of alloreactivity dominated both experiments and concepts. Considerable effort had been put into the study of graft rejection and the strong transplantation antigens. Could it be that these extremely potent immune responses, and the glycoproteins at which they were directed, had no physiological function other than the elimination of transplanted tissues? Was alloreactivity a phylogenetic remnant of the need to avoid mutual parasitism in primitive life forms, now used in complex vertebrates to limit th..