Immunosuppressive effect induced by intraperitoneal and rectal administration of boar seminal immunosuppressive factor.

The immunosuppressive component was isolated from boar seminal vesicle secretion and administered i.p. or rectally to male mice. By means of the immunofluorescent method, the seminal immunosuppressive component was found on the membranes of 50-70% of white blood cells of treated mice the first day after i.p. and the third day after rectal administration. The immunosuppressive component was observed on the membranes of 10-20% of white cells even at the 17th day after treatment. Intraperitoneal or rectal administration of the immunosuppressive component led to a decrease in the white cell concentration in blood of treated mice. These findings indicate that rectal deposition of semen may compromise some aspects of the immune system and may be an important cofactor in the development of viral or bacterial infections among homosexual men.