Minor Transplantation Antigens

Abstract

Transplantation or histocompatibility antigens were originally defined histogenically in vivo by exchanging tissue grafts between genetically dissimilar inbred strains of mice, their Fl, F2 hybrid and backcross (BC) progeny (Snell 1948). When two parental strains, PI and P2, reject each other’s grafts, both strains reject grafts from their F1 hybrid progeny, whereas F1 recipients accept grafts from either parental strain and all F2 and BC progeny (Fig. 1). These results established that transplantation antigens were eodominantly expressed. From the very small numbers of F 2 or BC donors whose grafts could be accepted by the parental strains, it was clear that a number of different histocompatibility (H) antigens were independently segregating. They were named sequentially H-l, H-2, H-3, etc., as they were identified and isolated by further backcrossing. The strongest of these, H-2, which elicited the most rapid graft rejection, was found to react with antibodies raised by Gorer using immunisation between inbred mouse strains: Gorer et al. (1948) then laid the foundation of serological analysis of the genetics and polymorphism of what we now know as the major histocompatibility complex (MHC), H-2 in mouse (Klein 1975), which has homologues in all mammalian species, including the human HLA system.