Purification and immunochemical characterization of group II pepsinogens in human seminal fluid.

Human seminal fluid has been shown to contain two pepsinogen fractions with the same electrophoretic mobilities as the group II pepsinogens (Pg II) in gastric and duodenal mucosa. These two fractions have been isolated from seminal fluid by column chromatography on diethylaminoethyl cellulose, gel filtration on Biogel P-150 and preparative acrylamide gel electrophoresis. Rabbit antiserum to the purified seminal pepsinogens formed a single precipitin arc against seminal fluid. This antiserum also formed a single precipitin arc against extracts of gastric and duodenal mucosa with a reaction of identity against all three antigens. Identical results were obtained with an antiserum to gastric Pg II. Neither the antiserum to the seminal pepsinogens nor the antiserum to gastric Pg II reacted against the group I pepsinogens (Pg I). Radioimmunoelectrophoresis with [I] seminal pepsinogens and antisera against Pg I-Pg II and human serum revealed radioactivity only in the precipitin arc which formed against Pg II. Radioelectrophoretic analysis of the [I] seminal pepsinogens produced a single radioactive zone. The results suggest that the pepsinogens preparation obtained from seminal fluid was pure, indicate that the pepsinogens in seminal fluid are electrophoretically and immunochemically identical to Pg II in gastric and duodenal mucosa, and provide further evidence for the existence of two immunochemically distinct groups of pepsinogens in man.