ABSTRACT
Objective:To study the mechanism of kidney-replenishing herb in regulating the tolerance of fetal-maternal interface and the effect of IDO on modulating the phenotype of decidual NK cells. Methods: Indoleamine-2,3-dioxygenase ( IDO) expression in villus tissues from normal pregnancies and recurrent spontaneous abortion (RSA) patients was monitored by immunohisto-chemistry (IHC). IDO expression in HTR-8/Svneo cells treated with control or herb serum medium was detected by flow cytometry (FCM). The influence of kidney-replenishing herb on modulating the phenotype of NK cells,CD16 and CD56 expression in peripheral NK cells co-cultured with control or herb serum medium in the presence or absence of 1-methyltryptophan (1-MT) treated HTR-8/Svneo cells were measured by FCM. Results: IDO expression was decreased in villus tissue of RSA patients compared to normal preg-nancies. Herb medium could increase the IDO expression of HTR-8/Svneo. Kidney-replenishing herb could enhance the regulatory function of trophoblasts on NK cells and further induce the immune tolerance at fetal-maternal interface in IDO dependent and independent manners. Conclusion: Kidney-replenishing herb can modulate the phenotype of peripheral NK cell by up-regulating IDO expression in trophoblasts and play a role in the treatment of RSA patients.