engleski

Unlike peripheral blood, first trimester pregnancy decidual NK cells spontaneously release high quantities of granulysin

Granulysin (GNLY) is a potent cytolytic protein and the first lymphocyte-derived molecule found to act as an alarmin, capable of promoting antigen presenting cell (APC) recruitment and adaptive immune response. The aim of study was to examine GNLY expression and distribution in early pregnancy decidua and peripheral blood (PB), the ability of decidual and PB NK cells to spontaneously secrete GNLY, and the regulation mechanisms of GNLY expression. Methods of study: Decidual mononuclear cells (DMC) were obtained by enzymatic digestion of decidual tissue and density gradient centrifugation. Peripheral blood lymphocytes were obtained by density gradient centrifugation. CD56+ cells were purified from the suspension of PBL or a non-adherent DMC fraction using positive magnetic separation after 18-hour culture at 37°C. The immature CD1a+ and subsequently CD14+ cells were isolated from the adherent DMC fraction. GNLY expression was analyzed using cell permeabilization method, flow cytometry and immunohistochemistry. GNLY secretion by purified NK cells was detected by ELISA method. Results: Granulysin expression in deciudal lymphocytes is twice higher compared with PBL of pregnant women. Decidual T lymphocytes express significantly higher levels of GNLY (58%) then PB T lymphocytes (11%). Over 85% of decidual CD56+ cells express GNLY. When cultured, unlike PB, decidual NK cells spontaneously release high quantities of GNLY. Decidual APC and IL-15 participate in the control of GNLY expression in CD56+ cells. Conclusion: Abundant expression of GNLY in the decidual immunocompetent cells and the capacity of decidual CD56+ cells to spontaneously secrete high quantities of GNLY points to important protective and immunomodulatory role that this molecule could play at the maternal-fetal interface. Acknowledgement: The investigation was financed by Croatian Ministry of Science, grant No. 0620402-0376 to Dr. D. Rukavina.

Granulysin; Pregnancy; Decidual mononuclear cells; NK cells

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