ABSTRACT

Thepredominantantithethicandpolymorphicantigens(MandN)thatarelocatedonthe glycophorins(GPs)orsialoglycoproteins(SGPs)inhumanredbloodcell(RBC)membranes werediscoveredabout65yearsagousingrabbitantibodies.MandNwereshowntobeencoded bycodominantalleles-however,itwasnoticedthatM+N-RBCs(genotypeMM)exhibita weakNantigen(nowdenotedas"N").About25yearsafterthediscoveryofMandN,two otherantitheticandpolymorphicantigens(Sands)werefoundandshowntobeencodedby genesthataregeneticallylinkedtoMandN,thusgeneratingfourpossiblehaplotypes:MS, Ms,NS,Ns.