title: Differential actions of progesterone and cortisol on lymphocyte and monocyte interaction during lymphocyte activation--relevance to immunosuppression in pregnancy.
abstract: Progesterone and glucocorticoids share important anti-inflammatory and immunosuppressive properties. Both hormones have potent anti-proliferative effects in MLR, mitogen activation and cytotoxic T-cell generation. We investigated the cellular target of this in vitro anti-proliferative activity by comparing the effects of progesterone and cortisol on lymphocyte-monocyte interaction in concanavalin (Con A) induced human T-cell activation. Three different in vitro systems for assessing monocyte dependent T-cell activation by Con A were used: (1) limiting concentration of monocyte, (2) preincubation of isolated populations of monocytes and T cells with steroids and (3) role of steroid on action of Interleukin-1 (IL-1) activity. Monocytes separated from human peripheral blood leukocytes by flotation gradients and adherence to plastic were cultured at concentrations of 0.5-10% with constant numbers of isolated autologous T cells. Inhibition of Con A activation in cortisol (0.1-10 micrograms/ml) treated cultures was inversely proportional to percent monocytes, whereas in progesterone (2.0-20 micrograms/ml) treated cultures, inhibition was independent of monocyte concentration. Separated monocytes preincubated with progesterone and cultured with fresh T cells supported normal (108 +/- 7% control) levels of activation, but progesterone treated T cells and fresh monocytes responded at about 60% control levels. Similar experiments with cortisol (1 or 10 micrograms/ml) revealed significantly reduced responses when either cell population was preincubated with steroid. IL-1 induced by LPS stimulation of monocytes was blocked in its ability to stimulate Con A induced T cell proliferation with either steroid present during the assay of IL-1. These data provide additional support for local immunosuppression by steroids in the placenta during pregnancy. They suggest that progesterone selectively blocks T cell activation by a direct effect on T cells, whereas cortisol interferes with both monocytes and T cells.
mesh_terms: D002478:Cells, Cultured; D003208:Concanavalin A / Q000494:pharmacology; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000494:pharmacology*; D007108:Immune Tolerance; D007375:Interleukin-1 / Q000096:biosynthesis; D008213:Lymphocyte Activation / Q000187:drug effects*; D009000:Monocytes / Q000276:immunology*; D011247:Pregnancy; D011374:Progesterone / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000276:immunology*
chemical_list: D007375:Interleukin-1; D003208:Concanavalin A; D011374:Progesterone; D006854:Hydrocortisone