Identification of sperm antigenic determinants with phylogenetically diverse and limited distribution using monoclonal antibodies

Mouse monoclonal antibodies capable of recognizing mouse sperm antigens were produced and the inter-species cross-reactivity of the antigenic determinants was examined. Of the seven clones independently established, it was found by indirect immunofluorescence staining that one was bound to the tail, one could recognize the head and five other antibodies reacted with the crescent-shaped anterior acrosome. Ultrastructural studies showed that the anti-head antibody recognized the sperm surface, and the anti-tail antibody reacted with the fibrous sheath. Five acrosomal antigenic determinants were found in the acrosome. These antibodies reacted with sperm from the male reproductive tract (testis, cauda epididymis, vas deferens), but not with somatic tissues. The anti-tail antibody reacted with sperm from four other mammalian species (musk shrew, rat, boar and human). The anti-head antibody and one of the anti-acrosome antibodies were bound only to mouse sperm. The other four acrosomal antigenic determinants showed various degrees of inter-species cross-reactivity. None of these antibodies reacted with chicken sperm.