Localization of human seminal plasma No. 7 antigen (Ferrisplan) in accessory glands of male genital tract and spermatozoa.

The establishment of a hybridoma (1C4) producing sperm immobilizing monoclonal antibody to human seminal plasma No. 7 antigen (HSP No. 7 Ag.) and the isolation of the pure antigen by immunoaffinity chromatography bound monoclonal antibodies have been reported previously. In the present investigation, HSP No. 7 Ag. has been termed 'Ferrisplan' and its distribution in male genital organs, spermatozoa and body fluids has been studied. The amount of Ferrisplan in the body fluids was determined by radioimmunoassay. Large amounts were detected in seminal plasma and milk, trace amounts in saliva, and none in the serum and urine. The concentration of Ferrisplan was highest in the seminal plasma of azoospermic patients and gradually decreased from oligospermia to normospermia. Using an immunofluorescent method with anti-Ferrisplan monoclonal antibody, strong staining was observed on the epithelial layers of human seminal vesicles, no staining on testes and bright staining on the post-nuclear cap and mid-piece segment of spermatozoa. These results indicate that Ferrisplan is excreted mainly from the seminal vesicle and adheres to the post-nuclear cap and mid-piece of the spermatozoa as a sperm-coating antigen.