The Role of γ/δ T-Cell Receptor-Positive Cells in Pregnancy: Part II

PROBLEM: We have previously demonstrated a significantly increased ratio of γ/δ T‐cell receptor (TCR)‐positive progesterone receptor(PR)‐positive cells in the peripheral blood of healthy pregnant women compared to that of recurrent aborters or non‐pregnant individuals. Treatment of pregnancy lymphocytes with a pan anti‐γ/δ TCR antibody inhibits progesterone‐induced blocking factor (PIBF) production, increases natural killer (NK) activity, and alters the cytokine profile. The present study was aimed at investigating the role of the different γ/δ subpopulations in these phenomena. METHOD OF STUDY: Peripherial blood lymphocytes from healthy pregnant women were incubated with either anti‐γ1.4 and δ1, or anti‐γ9 and δ2 antibodies. The effect of these treatments on PR induction and interleukin (IL)‐10 and IL‐12 expression were tested by immunocytochemistry. NK activity of anti‐γ/δ treated lymphocytes was also determined. RESULTS: In peripheral blood of healthy pregnant women, the most frequently occurring chain combination was γ1.4/δ1, whereas in recurrent aborters, the γ9/δ2 combination was predominant. Treatment of normal pregnancy lymphocytes with a mixture of γ1.4 and δ1 antibodies resulted in a significantly reduced NK activity and increased PR and IL‐10 expression, whereas treatment with a mixture of γ9 and δ2 antibodies significantly reduced IL‐10 production and slightly increased IL‐12 production and NK activity. These data suggest the presence of two functionally distinct subpopulations in the peripheral blood of pregnant women.