Maternal T Regulatory Cell Depletion Impairs Embryo Implantation Which Can Be Corrected With Adoptive T Regulatory Cell Transfer.
Maternal immune tolerance of fetal engraftment is critical for the establishment and maintenance of pregnancy, but the exact mechanisms permitting this semi-allograft in the maternal host are not completely understood. Further, failure of the embryo to implant in the uterus accounts for at least 30% of the best prognosis in vitro fertilization cycles when a perfect embryo is transferred to a normal uterus. We hypothesized that T regulatory cells (Tregs), defined by CD4+CD25hi surface expression and the FoxP3+ transcription factor, play an important role in the initiation of the earliest stages of pregnancy, specifically implantation of the embryo. In this study, we evaluated the role of Tregsin the establishment of pregnancy using a conditional depletion of Tregtransgenic mouse model. We found that embryo implantation in the syngeneic mating was defective as evidenced by smaller litter sizes after Tregdepletion and that embryo implantation could be restored by adoptively transferring Tregsinto the mating mice. In allogeneic mating, litter sizes were not different but breeding efficiency was significantly decreased. These data reveal that Tregsare important for the establishment of the earliest stages of pregnancy and may be a potential cause of infertility due to recurrent implantation failure, which may be amenable to cellular or pharmacologic therapy to improve maternal immune tolerance of embryo implantation.
1 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.|2 Walter Reed National Military Medical Center, Bethesda, MD, USA.
Ryan J
RJ
Heitmann
3 National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
R Patrick
RP
Weitzel
1 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
Yanling
Y
Feng
1 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.
James H
JH
Segars
3 National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
John F
JF
Tisdale
1 Program in Reproductive and Adult Endocrinology, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA.|3 National Heart, Lung and Blood Institute, National Institutes of Health, Bethesda, MD, USA.
Erin Foran
EF
Wolff
D019264:Adoptive Transfer; D000818:Animals; D010064:Embryo Implantation / Q000276:immunology*; D005260:Female; D008212:Lymphocyte Depletion; D051379:Mice; D008822:Mice, Transgenic; D011247:Pregnancy; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*; D014599:Uterus / Q000276:immunology*
T regulatory cells; implantation; murine model; pregnancy establishment