A study of reproductive performance in pregnant, IL-2 receptor beta-chain overexpressed transgenic mice

Relationships between female reproductive performance and uterine natural k iller (uNK) cells were investigated in pregnant IL-2 receptor beta -chain o verexpressed transgenic (Tg2R beta) mice. At 8 days of pregnancy, all fetus es were alive, suggesting that implantation normally occurred in these mice . However, 47% of fetuses were dead at 10 days of pregnancy and at 12 days all fetuses were resorbing, indicating that fetal loss progressed with the advance of pregnancy. The placenta of Tg2R beta mice gradually decreased in weight with the advance of pregnancy. At 10 days the placental labyrinth, decidua basalis, and metrial gland in Tg2R beta mice were poorly developed, and more uNK cells were found in Tg2R beta mice than in the control mice. We propose that Tg2R beta mice are the first and interesting model that uNK cells can cause abortion, to clarify the involvement of uNK cell function in female reproductive performance.