In vivo and in vitro immunosuppression by boar seminal vesicle fluid fraction.

Boar seminal vesicle fluid inhibits blast transformation of porcine lymphocytes. Boar seminal vesicle fluid was precipitated in 8% ethanol and the dissolved precipitate separated into two peaks upon chromatography on a Sephacryl S-200 column. The inhibitory activity was found predominantly in the second peak. This peak was rechromatographed on the Sephacryl S-200 column, and the fractions with inhibitory activity were pooled and passed down a Sephadex G-75 column. This chromatography run separated the accompanying protease inhibitor from the immunosuppressive fraction. The molecular mass, estimated by chromatography on the Sephadex G-75 column, was 25,000-27,000 for the immunosuppressive factor and 7,500 for the protease inhibitor. Activity for the immunosuppressive fraction was also demonstrated in vivo.