Testis antigens of man and some other primates

Rabbit antisera raised aginst testis preparations of human, chimpanzee, rhesus monkey, and baboon origin were used to study testis-specific antigens within and among the four primate species. Antisera were absorbed with serum, liver, kidney, and spleen preparations of the respective species against which they had been produced. Immunoelectrophoretic analysis of testis extracts, using the absorbed antisera, indicated the following minimum numbers of testis-specific antigens for each species: man, 10; chimpanzee, 8; rhesus monkey, 10; and baboon, 8. Most of the testis antigens were cross-reactive among species. The results suggest that human spermatozoa possess at least four to five specific antigens which originate in the testis. The antigen that induces sperm-immobilizing antibody cross-reacted among the four species of primates. Human and rhesus monkey sperm reacted equally in the immobilization system. Testis extracts from each primate species were capable of removing the sperm-immobilizing activity of human immune sera by absorption. Testis proteinase activity, as determined by using a gelatin membrane substrate, was inhibited by the gamma-glogulin fractions of rabbit and rhesus monkey antisera and also appeared to be cross-reactive among the species.