Immunocompetence in pregnancy: production of interleukin-2 by peripheral blood lymphocytes

Pregnancy is a natural allograft and the mechanisms for its non-rejection are obscure. Depression of maternal cellular immunity was suggested as a possible explanation. Interleukin-2(IL-2) is a lymphokine release from OKT4+ lymphocyte. This factor has a crucial role in the proliferation and differentiation of T cell subsets, and controls functions associated with immune rejection mechanisms. We therefore examined the ability of lymphocytes from women in the 3 trimesters of pregnancy to produce IL-2 in culture. Mononuclear cells were cultured with PHA for 48 h. The IL-2-containing supernatant was added to and supported the proliferation of an IL-2 dependent T cell line. Proliferation of this line indicated the IL-2 content of the added supernatant. Using this assay, IL-2 production in all 3 trimesters of pregnancy was adequate and comparable to that of lymphocytes from non-pregnant women. These results suggest that the proposed defect in cellular immunity during pregnancy is not mediated by an inability of the lymphocytes to produce IL-2.