Abstract

When mononuclear cells infiltrating rabbit testes infected with Treponema pallidum were cocultured with autologous or homologous peripheral blood lymphocytes spontaneous stimulation and that induced by concanavalin A were suppressed. The inhibition was not due to the cytotoxic effect of the mononuclear cells or to their interference with the active site of concanavalin A (competitive inhibition). The suppressor activity was present in both T and non-T cells but was not affected by pretreatment of the mononuclear cells with indomethacin, a prostaglandin synthetase inhibitor. The suppressor activity may be intrinsic to the mononuclear cells or acquired by the cells in the testicular environment.