LAUSR

OBJECTIVE To investigate whether epigenetic modification of CD4+CD25- T-cells in vitro can make up for the inadequacy of CD4+CD25+Foxp3+ Treg in animal model of spontaneous abortion and prevent immune response-mediated spontaneous abortion. METHODS Trichostatin A (TSA) was applied to inhibit histone deacetylases (HDACs) and thereby to epigenetically modify the special location of Foxp3 gene in CD4+CD25- T-cells of CBA/J mice. The expressions of CD25, Foxp3, CTLA-4 and PD-1 of CD4+ T cells isolated from spleen of mice were characterized by flow cytometric analysis. Concentrations of transforming growth factor- β (TGF-β) and IL-10 in the supernatants of cultured Treg were measured using ELISA. The purified CD4+ T cells treated with different reagents were injected into pregnant CBA/J mice mated with DBA/2J males on Day 1 and 4 of pregnancy, respectively. The embryo resorption rate was assessed on Day 14 of pregnancy. RESULTS TSA treatment significantly increased the population of CD4+CD25+Foxp3+ iTreg. Those TSA induced Treg expressed high levels of PD-1 and CTLA-4, and secreted high levels of TGF-β and IL-10. Adoptive transfer of those iTreg at both early stage and implantation of stage of pregnancy significantly increased population of CD4+CD25+Foxp3+ Treg in spleens of recipient miscarriage prone mice and significantly reduced resorption in those mice. CONCLUSION Epigenetic regulation of Foxp3 can generate functional regulatory T-cells. Adoptive transfer of TSA- induced CD4+CD25+Foxp3+ Treg at an early stage of pregnancy can induce maternal-fetal immune tolerance and reduce embryo resorption in miscarriage prone mice.