MONOCLONAL-ANTIBODIES DIRECTED AGAINST HUMAN RH ANTIGENS IN TESTS WITH RED-CELLS OF NONHUMAN-PRIMATES

Human anti-D (Rh-o) monoclonal antibodies (Mabs) of the IgG (70) and I gM (27) classes were tested with red blood cells (RBCs) of various non -human primates, from anthropoid apes to New World monkeys. Significan t differences in reactivity were observed among antibodies of two clas ses depending on taxonomic position of primate animals. Only IgM Mabs gave positive reactions (9 out of 18 Mabs) with blood of Old World mon keys. Allotypic reactions with RBCs of African apes were produced by a majority of IgG Mabs but by very few IgM reagents, most of the latter reacting with RBCs of all chimpanzees and all gorillas tested. Eight out of 70 IgG anti-D defined chimpanzee polymorphisms related to chimp anzee R(c) antigen which is the chimpanzee counterpart of human D anti gen. Most of IgG anti-D Mabs (61/70) were found specific of D-gor anti gen (gorilla counterpart of human antigen D). Most of anti-D which wer e found negative with all chimpanzee RBCs were also negative with huma n D-IVb RBCs and most of anti-D which agglutinated human D-IVb RBCs we re positive with some or all chimpanzee blood samples. Differences amo ng Mabs evidenced in tests with non-human primate RBCs reflect the com plexity of the immune reactions to the human D antigen. The results ob tained with anti-lih Mabs of specificities other than D confirmed that chimpanzee, gorilla and gibbon express c-like epitopes and that antig ens C, E, e are absent in non-human primates.