Effect of gonadal steroids on proliferative responses and subset alterations in cultured chicken lymphocytes

The effect of gonadal steroids (GS) on proliferation of lymphocytes and dis tribution of lymphocyte subpopulations in cell culture was examined. The in volvement of protein kinase C (PKC) and calcium ionophore in the proliferat ive response was tested. Estradiol benzoate (EB) or testosterone propionate (TP) had no significant influence on proliferation of peripheral blood lym phocytes (PBL) when cells were not stimulated by mitogen. At high concentra tion (10(-6) M), EB and dihydrotestosterone (DHT) decreased lymphocyte prol iferative response to concanavalin A (ConA) and lipopolysaccharide (LPS) at 24 and 72 h of incubation. However, at physiological doses (10(-12) to 10( -16) M), EB significantly enhanced the proliferative response at 24 h of in cubation, whereas DHT had no effect. The inhibitory effect of the high dose of EB or DHT on proliferation of T and B lymphocytes was independent of ti me of hormone presentation to the cells or age and gender of cell donor. In all cultures, pre-incubation of lymphocytes with 10(-6) M of EB or DHT sig nificantly reduced their proliferative responses to ConA, phytohemagglutini n (PHA), and LPS. The percentage of CD3(+) cells was significantly reduced by EB, whereas DHT had no such effect. In contrast to inhibition of prolife ration in response to mitogens, 10-6 M EB dramatically enhanced the prolife ration of lymphocytes in response to the PKC activator, phorbol 12-myristat e 13-acetate, and calcium ionophore, A23187. Results suggest that high dose s of EB do not damage the viability or proliferation capability of lymphocy tes and, therefore, suppress the proliferative response to mitogens in a di fferent manner, perhaps by reducing gene transcription for receptors that r ecognize the mitogens, or suppressing some postreceptor events. The enhance ment of proliferation in response to mitogens by low doses of EB may suppor t this assumption, because the biphasic effects of steroids on gene transcr iption are well documented.