The Blood Grouping of Macacus Rhesus

The species Macacus rhesus cannot be divided into blood groups. In this respect the species behaves like pure-bred human races (Eskimos, North American Indians, etc.). Macacus rhesus erythrocytes have no antigen identical with or closely related to either of the two human isoagglutinogens (A or B). Rhesus serums, however, contain a hemagglutinin which is indistinguishable from the α isoagglutinin possessed by certain human serums. The anti-A agglutinin titer of rhesus serums can be raised by immunization of the animal with human red cells of group A. This enhancement of titer apparently is due to stimulation by the specific A isoantigen, since red cells of groups O or B have no such effect. The injection of human cells of group B, on the other hand, did not cause the formation of anti-B agglutinins de novo. The erythrocytes and organs (kidney) of Macacus rhesus and man possess an antigen in common. This antigen resembles the human isoantigens since it is alcohol soluble and heat stable. Rhesus monkeys inoculated with human red cells of groups O, A or B produce agglutinins for all human cells, regardless of their blood group. The antigen which causes this serological response is apparently species specific. It is not alcohol soluble. The species Macacus rhesus belongs to the so-called Forssman negative or rabbit group, since heterophile antigen is absent in its erythrocytes or organs, while a normal heterophile lysin or Forssman antibody is present in its serum.