Study on the expression of Fas ligand on the surfaces of human cytotrophoblasts in normal pregnancy.

To further study the mechanism of maternal-fetal immune tolerance, the expression of Fas ligand (FasL) on the surfaces of human cytotrophoblasts in normal pregnancy was detected by using immunohistochemical method. High precise color-image measure system for immuno-histochemistry was used to quantitatively analyze the expression of FasL. The results showed that FasL were expressed on the surfaces of placental cytotrophoblasts throughout normal pregnancy. The variance among the first, second and term pregnant stages was also detected. It was suggested that the expression of FasL on the surfaces of placental cytotrophoblasts might play an important role both in the maintenance of pregnancy and in the normal development of fetus. The maternal specific T cell apoptosis induced by Fas/FasL is one of the significant mechanisms of maternal-fetal immune tolerance.