Role of transforming growth factor beta in testicular immunosuppression.

The potential role of transforming growth factor beta (TGF beta) in the regulation of the immunological milieu of the testis was investigated. Antibodies neutralizing TGF beta reversed the previously observed suppression of rat peripheral blood lymphocyte proliferation induced by rat abdominal testis extract. Recombinant TGF beta 1 dose-dependently inhibited testicular interleukin-1-like factor-driven proliferation of murine thymocytes and ConA-stimulated rat peripheral blood mononuclear cells. Extracts of seminiferous tubules contained a M(r) approximately 25 K TGF beta-like growth inhibitor of the CLL-64 mink lung epithelial cell line. The present findings suggest an important role for TGF beta in testicular immunosuppression.