Effects of dihydrotestosterone, 17 beta-estradiol and dexamethasone on mitogen--and allogeneic--induced lymphoblastogenesis.

In contrast to the in vivo action of sex steroids the steroidal hormones dihydrotestosterone (DHT) and estradiol (E2) produced a marked variable response on mitogen-induced lymphoblastogenesis. DHT and E2 at concentrations of 10(-11) mol l-1 incubated with mononuclear cell fraction in the presence of mitogens PHA, Con A and PWM caused inhibition, stimulation or no effect. Separation of T and B cell fractions and incubation with DHT and E2 likewise produced variations in response. However, dexamethasone (DEX) strongly inhibited proliferation of all cell fractions, particularly at the higher steroid concentrations. These results suggest that the reported effects of in vivo administered sex hormones on the immune system might possibly be mediated by a precursor cell of peripheral blood mononuclear cells, and that the in vitro system may not be a reproducible test for determining an individual's immunoendocrine status.