Seminal plasma inhibits lymphocyte response to T-dependent and -independent antigens in vitro

The effect of seminal plasma, epididymal spermatozoa, or whole semen on antibody producing cells was examined in vitro after (i) direct culture with spleen or B cells, and (ii) cocultivation of B cells with T cells previously incubated with seminal plasma. Seminal plasma, and not epididymal spermatozoa, have an inhibitory effect on the direct hemolytic plague forming cell response. This was mediated by a direct inhibitory effect on the B cell and not through the generation of suppressor T cells as demonstrated by responses to T-independent and -dependent antigens. Thus, the mode of suppressive action of seminal plasma in vitro is probably different from that previously reported in vivo.