Monoclonal anti-LWab and anti-D reagents recognize a number of different epitopes. Use of red cells of non-human primates.

Monoclonal antibodies (mAbs) which detect antigens on human red cells are also suitable for testing cells of other species. Such studies may reveal previously unrecognized heterogeneity in antibodies which apparently detect the same antigen on the human red cell surface. Information is also provided on specificities shared amongst several species. Here three anti-LWab and a variety of Rh-related antibodies have been tested against the red cells of various primates. One monoclonal anti-LWab antibody, BS46, reacted with the red cells of gorillas and rhesus monkeys but not those of orang-utans, baboons or marmosets. In contrast, BS56 and NIM-M8 reacted with the cells of all these species. Chimpanzee cells, however, reacted only with NIM-M8. Use of primate cells has shown that all three monoclonal anti-LWab antibodies recognize different epitopes. These observations may explain early conflicting data concerning primate cells. The difference between the monoclonal anti-D, D4, and three other anti-D antibodies, 8G2, 8D6 and 7D10, has been confirmed. The D antigen is apparently confined to the red cells of apes and humans. D4 recognizes a polymorphism in chimpanzees and 8G2, 8D6 and 7D10 recognize a polymorphism in gorillas. Two Rh-related mAbs, R6A and K70, were also investigated. R6A fails to react with Rhnull cells and reacts more weakly with homozygous-D-cells than with cells of common Rh phenotypes. K70 reacts weakly with Rhnull and -D-/-D- cells. The antigen detected by R6A is confined to the red cells of humans, gorillas and chimpanzees, while the antigen detected by K70 shows a wider species distribution. In some primates LW antigens are expressed in the absence of the determinant recognized by R6A. This phenotype has never been known to occur in humans.