Dynamics of a human seminal vesicle specific protein.

The present paper is concerned with the temporal alterations and tissue localization of a seminal antigen secreted by the human seminal vesicle. This antigen is recognized by antibody MHS-5, which is one of a set produced in mice by immunization with human sperm. The respective clone produced an antibody of the IgG1 subtype, which reacted with seminal fluid from over 400 normal donors and 21 semen samples from vasectomized men. Incubation of seminal vesicle secretion with either prostatic fluid or prostate specific antigen (PSA) resulted in degradation on the antigen. The experiments showed that MHS-5 antigen is a substrate for the serine protease PSA: Immunohistochemical studies suggested that MHS-5 is a "sperm-coating" antigen and is exclusively synthesized and secreted by the seminal vesicle.