Immunohistochemical localization of phospholipase A2 in human and bovine male reproductive organs.

Phospholipase A2 (PLA2) taken from human seminal plasma and purified about 1450-fold was injected into rabbits to prepare polyclonal antibodies. The antiserum produced and the IgG purified from the antiserum were used to compare the immunohistochemical localization of PLA2 in the human male reproductive system with that in the bull. In Western blot analyses, the polyclonal antibodies cross-reacted with purified PLA2s from human seminal plasma, bovine Cowper's glands and with partly purified PLA2 from bovine seminal vesicle fluid. On the other hand, purified PLA2s from Crotalus adamanteus venom, bovine pancreas or from bovine prostate were not recognized by the polyclonal antibodies. With an indirect peroxidase technique, PLA2 was localized in the epithelial cells of the human prostate and bovine seminal vesicles as well as in the fibrous connective tissue of bovine Cowper's gland. Indirect peroxidase staining also gave an immunoreaction in the enlarged acrosomes of round spermatids in the human testis. Using an indirect immunofluorescence method, ejaculated human spermatozoa revealed an immunoreaction which was not uniform, and the reaction was restricted to the middle piece and the acrosomal and postacrosomal regions. In conclusion, human seminal plasma, spermatozoa and prostate PLA2s were immunohistochemically related to those from bovine Cowper's gland, seminal vesicles and seminal fluid.