Human and guinea-pig cross-reacting spermatozoa autoantigens and autoantibodies

Cross-reactivity between human and guinea-pig spermatozoa autoanigens has been studied in two systems: (1) guinea-pig anti-autoantigens S, P and T immune sera reacting on human spermatozoa and (2) activity of human anti-sperm sera on guinea-pig spermatozoa. These assays, as well as the results of cross-absorptions in the two systems, revealed a close antigenic relationship between the two species of spermatozoa concerning the guinea-pig autoantigen S. However, there were some differences in its localization and serological manifestations in both species. The guinea-pig autoantigen T bore a more distant, though definite, relationship with human spermatozoa. No clear evidence of cross-reactivity between the two species was found for autoantigen P. At variance with autoimmune (or isoimmune) human antibodies, 'natural' human antibodies active on guinea-pig spermatozoa were absorbed by guinea-pig spleen cells.