The importance of fetal antigen specific regulatory T cells in allogeneic pregnancy

Regulatory T（Treg） cells play an essential role for induction of feto-maternal tolerance. To understand the pathophysiology of unknown etiology of recurrent pregnancy loss and implantation failure, we have studied the paternal（fetal)antigen-specific Treg cells using mouse model. Paternal antigen specific Treg cells had paternal antigen specific immunosuppressive activity. Furthermore, paternal antigen specific Treg cells increased in the draining lymph nodes just before implantation , and in the uterus after implantation in allogeneic pregnant mice, but not in syngeneic pregnant mice.