Abstract
To investigate whether progesterone plays an essential role in differentiation of uNK cells, we ectopically transplanted tissue grafts from different developmental stages of uteri under various conditions. When female mice were used as recipients, decidualization and differentiation of uNK cells were observed in grafts from mature (8 weeks old) and immature (4 weeks old) donors, but there was no change in grafts from postnatal (10 days after birth) donors. When immature female mice were used as recipients, uNK cell differentiation was observed in grafts from both mature and immature donors, but decidualization and differentiation of uNK cells were not observed in the recipient uterus even in the presence of progesterone. These results suggest that uNK cell differentiation is not associated with the sexual maturation of recipients, and that the effect of progesterone on uNK cell differentiation is not direct, even though progesterone is an essential factor for uNK cell differentiation. When male mice were used as recipients, decidualization and differentiation of uNK cells were not observed in uterine grafts from normal mature mice. On the other hand, in castrated recipients uNK differentiation was induced in the graft, suggesting that uNK cell cannot fully differentiate in the presence of testosterone.
