COMPARATIVE-STUDY OF HUMAN MONOCLONAL ANTI-D ANTIBODIES OF IGG AND IGM CLASSES IN TESTS WITH RED-CELLS OF NONHUMAN-PRIMATES

Forty-nine human anti-D (Rh-o) monoclonal antibodies of the IgG and Ig M classes were tested with red blood cells of various nonhuman primate s, from anthropoid apes to Prosimians, and significant differences in reactivity were observed among antibodies of two classes depending on taxonomic position of primate animals. By and large, higher percentage of IgM mAbs gave positive reactions with nonhuman primate red cells a nd, particularly, with blood of lower monkeys : Old and New Worlds mon keys and Prosimians, than did those of IgG class. Allotypic reactions with red cells of African apes were produced by majority of IgG mAbs b ut by very few IgM reagents. Some of those reactions defined epitopes related to human D, such as chimpanzee R(c) and gorilla D-gor. By cont rast, individual differences among Old World monkey species were revea led almost exclusively in tests using anti-D mAbs of IgM class. Some o f the epitopes detected by these antibodies on the red cells of macaqu es ave related to human D alloantigen, as confirmed by absorption expe riments. Differences among mAbs evidenced in tests with nonhuman prima te red cells reflect the complexity of the immune reactions to the hum an D antigen.