Monoclonal antibodies to human sperm antigens.

To elucidate the molecular nature of human sperm autoantigens, attempts were made to raise monoclonal antibodies against these antigens, by hybridoma techniques. After successive immunizations with the particulate fractions of human sperm extract in BALB/c mice, the spleen cells were fused with P3-X63-Ag8 myeloma cells. Several clones and their subclones were obtained and shown by microplate radioimmunoassay to produce antibodies against human sperm antigens. When SDS gel/protein blot radioimmunobinding was used for further molecular analysis, three independently derived clones were shown to produce antibodies, all of which cross-reacted with the same two human sperm antigens with a molecular weight of about 10,000. Using an indirect immunofluorescence assay, antibodies produced by these clones were shown to react with antigens localized on the acrosomal regions of human spermatozoa. Monoclonal antibodies produced by other clones, however, showed no cross-reactivity with any of the blotted proteins from SDS gels of human spermatozoa. Some possible reasons for this are presented.