title: Role of guinea-pig sperm autoantigens in capacitation and the acrosome reaction.
abstract: Three autoantigens, S, P and T, have been isolated from epididymal spermatozoa of guinea-pigs. S and P are soluble antigens present on the acrosomal membranes and acrosome matrix. T antigen, a family of several membrane glycoproteins, is distributed over the whole cytoplasmic membrane and on the external acrosomal membrane. Specific antibodies were used to localize the antigens on capacitated and acrosome-reacted spermatozoa and to define their role in acrosome reaction. After capacitation S antigen appeared on the head surface and there was an apparent clustering of T antigen. Both phenomena were prevented by the presence of specific antibodies in the capacitating medium. The acrosome reaction was inhibited both by anti-T and anti-S antibodies as well as by Fab fragments of the same antibodies. The localization of S, P and T antigens on the inner acrosomal membrane after the acrosome reaction suggests that they could also play a role in subsequent steps of fertilization.
mesh_terms: D000177:Acrosome / Q000276:immunology / Q000502:physiology; D000818:Animals; D000941:Antigens / Q000032:analysis; D001324:Autoantigens / Q000032:analysis; D005260:Female; D005307:Fertilization in Vitro; D006168:Guinea Pigs; D008297:Male; D008561:Membrane Fusion; D010063:Ovum / Q000502:physiology*; D013075:Sperm Capacitation; D013077:Sperm Head / Q000276:immunology; D013094:Spermatozoa / Q000276:immunology / Q000502:physiology*; D015044:Zona Pellucida / Q000276:immunology / Q000502:physiology*
chemical_list: D000941:Antigens; D001324:Autoantigens