engleski

The influence of Th1 cytokines on perforin and Fas/FasL mediated cytotoxicity of first trimester pregnancy decidual and peripheral blood lymphocytes

During normal human pregnancy Th2 cytokines have been found to predominate in peripheral blood and at the maternal-fetal interface, while pregnancy failures have been related to high levels of Th1 cytokines. CD56bright+ decidual NK (dNK) cells that constitute 70-80% of all decidual lymphocytes in early pregnancy are thought to play a major role in regulating implantation and trophoblast invasion. The high cytolytic potential of these cells is maintained by high concentration of pore forming protein perforin stored in numerous granula. The aim of the study was to investigate the influence of Th1 cytokines on the cytotoxicity of first trimester pregnancy decidual (DL) and peripheral blood lymphocytes (PBL) and the possible cytolytic mechanisms involved. Decidual tissue and peripheral blood cells were obtained from elective termination of normal human pregnancy (6-10 weeks). Decidual tissue was enzymatically digested. Decidual and peripheral blood mononuclears (DMC and PBMC) were obtained by density gradient centrifugation. DL and PBL were cultured for 18 or/and 72 hrs in the medium or in the presence of Th1 cytokines. Decidual (dNK) cells were purified by positive magnetic cell separation method immediately after isolation of DMC or following 18 hrs culture in the medium. Cytotoxicity assay PKH-26 (red) cell linker kit, direct and indirect immunofluorescency were analyzed by flow cytometry. DL cultured in the medium lysed NK sensitive (K562) and NK resistant (P815 and P815Fas) targets while PBL were cytotoxic only against K562 cells. Th1 cytokines induced PBL cytotoxicity against P815 and P815Fas cell lines but did not influence DL cytotoxicity. However, PBL and DL stimulated with Th1 cytokines lysed more P815Fas, than P815 cells. Concanamicyn A and anti-FasL antibody decreased the cytotoxic activity of decidual CD56+ cells against P815 cells. Approximately 7% of CD56bright+ cells expressed FasL after IL-15 stimulation of DMC. Early pregnancy DL cells cultured for 18 hrs in the medium are activated and use both cytolytic mechanisms for killing NK resistant cell lines in vitro. It seems that perforin and FasL expression at the maternal-fetal interface is highly regulated, probably by complex cytokine network, since the cytotoxicity of activated dNK cells could be directed against trophoblast and lead to pregnancy failure.

Th1 cytokines; Th2 cytokines; pregnancy; lymphocytes; decidua; peripheral blood lymphocytes

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