Indeed, there is mounting evidence from clinical trials of the efficacy of progesterone in women with recurrent miscarriage or high risk of preterm delivery 13, 14, 33

Indeed, there is mounting evidence from clinical trials of the efficacy of progesterone in women with recurrent miscarriage or high risk of preterm delivery 13, 14, 33. that this as a direct, nonantigen\specific effect. Yet human T?cells lacked conventional nuclear progesterone receptors, implicating a membrane progesterone receptor. CD4+ and CD8+ T?cells responded to progesterone in a dose\dependent manner, GZ-793A with subtle effects at concentrations comparable Tmem26 to those in maternal GZ-793A blood, but profound effects at concentrations similar to those at the maternalCfetal interface. This characterization of how progesterone modulates T\cell function is important in understanding the normal biology of pregnancy and informing the rational use of progesterone therapy in pregnancies at risk of fetal loss. = 1, experiment in triplicate) were treated with PHA and increasing concentrations of progesterone (P4) from 0.5 to 100 M. The effect of progesterone treatment on the production of IFN\, TNF\, IL\4, IL\17, IL\5, and IL\10 was measured by flow cytometry. Data are shown as mean + SEM from a single experiment. The pattern of cytokine production within CD8+ and CD4+ T?cells was comparable between maternal and control cells (Fig. ?(Fig.1).1). Suppression of IFN\, TNF\, IL\5, and IL\10 appeared to start at a slightly lower progesterone concentration in maternal cells compared to the controls, warranting more detailed examination of this. Based on this initial data, and taking into account physiological levels of progesterone during pregnancy, we selected progesterone concentrations of 1 1 and 10 M as a basis for detailed studies on T\cell function. Progesterone reduces IFN\, TNF\, IL\5, and IL\10 and increases IL\4 production by CD8+ T?cells The effect of incubation with 1 or 10 M progesterone on the cytokine profile of activated CD8+ T?cells from a range of maternal donors (= 13) was assessed by flow cytometry (Fig. ?(Fig.2A;2A; additional gating strategy shown in Supporting Information Fig. 1). Overall, compared to treatment with vehicle control, treatment with 10 M progesterone resulted in a significant decrease in the mean percentage of CD8+ T?cells expressing IFN\ (53.3 vs. 36.6%, < 0.0001), TNF\ (55.2 GZ-793A vs. 43.3%, < 0.0001), IL\5 (65.6 vs. 50.6%, < 0.0001), and IL\10 (65.9 vs. 53.7%, < 0.0001; Fig. ?Fig.2B).2B). Exposure to 1 M progesterone also produced a significant reduction in the percentage of CD8+ T?cells expressing IFN\ (53.3 vs. 47.3%, < 0.01; Fig. ?Fig.2B)2B) although the influence on the other cytokines was less marked. Open in a separate window Figure 2 Treatment of maternal PBMCs with physiological concentrations of progesterone alters the cytokine expression of CD8+ T?cells. PBMCs from healthy maternal donors were treated with PHA and either DMSO (vehicle), or 1 or 10 M progesterone. The effect of progesterone treatment on production of IFN\, TNF\, IL\4, IL\17, IL\5, and IL\10 was measured by flow cytometry. (A) A representative flow plot of PBMCs from one patient treated with DMSO and 10 M progesterone (P4) is shown. (B) The cytokine expression of maternal CD8+ T?cells GZ-793A overall when treated with different progesterone concentrations or vehicles is shown as mean + SEM of 13 donors. * 0.05, ** 0.01, *** 0.001, **** 0.0001, one\way ANOVA, repeated measures, and Bonferroni multiple comparison. Interestingly, treatment with 10 M progesterone significantly increased the percentage of CD8+ T?cells expressing the Th2 cytokine IL\4 compared to vehicle control (3.6 vs. 5.6%, < 0.05; Fig. ?Fig.2B).2B). No significant changes in the percentage of these lymphocytes expressing IL\17 was observed, with very low percentages of cells expressing this cytokine. Progesterone reduces IFN\, TNF\, IL\5, and IL\10 and increases IL\4 production by CD4+ T?cells The effect of progesterone on cytokine production by CD4+ T?cells was also examined in maternal donors (= 13; Fig. ?Fig.3).3). The influence of progesterone on cytokine production from CD4+ T?cells was comparable to that seen for CD8+ cells although effects were somewhat more marked. Treatment of PBMCs with 10 M progesterone resulted in a decrease in the percentage.