Inhibin and Activin Modulate Transforming Growth Factor-beta-Induced Immunosuppression

Inhibin, activin, and transforming growth factor beta (TGFbeta) inhibited lipopolysaccharide (LPS)-induced lymphocyte proliferation in a dose-dependent fashion. These induced suppressions were neutralized by coincubation of a preparation of antibodies to inhibin and TGFbeta, respectively. Inhibin and activin also facilitated TGFbeta-mediated immunosuppression of LPS-induced proliferation of splenocytes. These gonadal proteins showed no effect on phytohemagglutinin- or concanavalin A (Con-A)-induced proliferation of lymphocytes. However, inhibin facilitated and activin inhibited the TGFbeta-mediated immunosuppression in thymocytes stimulated by Con-A. These findings suggest that inhibin or activin by itself, and/or together with TGFbeta, may play an important role in immune response. Copyright 1995 S. Karger AG, Basel