EFFECT OF 17-BETA-ESTRADIOL ON IMMUNOGLOBULIN SECRETION BY HUMAN TONSILLAR LYMPHOCYTES IN-VITRO

Sex steroid hormones play a role in the complex network of immune resp onse but the mechanism of their action is still unclear. Effects of a wide range of doses of 17beta -estradiol (E2: 0.2-100 ng/ml) on human tonsillar lymphocyte cultures were examined. B and T lymphocyte enrich ed preparations were stimulated with various concentrations of interle ukin-2 and the production of immunoglobulin was measured. Addition of E2 increased B cell immunoglobulin production in a T cell dependent wa y with intact T cells being obligatory. The effects of E2 were also ex amined on DNA synthesis by tonsillar T cells. E2 alone caused a signif icant increase in T cell DNA synthesis. With phytohaemagglutinin-stimu lated T cell cultures there was a significant increase in DNA synthesi s with E2 at pharmacological doses. Different cell surface and activat ion markers (including CD25, p75, HLA-DR, CD28) on tonsillar lymphocyt es were also studied after exposure to E2. The presence of E2 made no significant difference in the expression of the markers either alone o r when the activation antigens were induced by other stimuli. We have shown that intact T cells are needed for the action of E2 on tonsillar B lymphocyte differentiation and have excluded several mechanisms of action of E2 since common activation antigens are unaffected.