Physiological Dose of Estrogen Regulates Extrathymic T Cells in Female Mice

Bilateral ovariectomy was performed in female C57BL/6 mice to investigate whether extrathymic T cells in the liver are regulated by physiological doses of estrogen or progesterone. Extrathymic T cells were identified using a two-color immunofluorescence test for CD3 and interleukin-2 receptor β-chain (IL-2Rβ) antigens. The T cells were identified as intermediate CD3+cells with a high expression of IL-2Rβ. It was further demonstrated that the proportion and number of intermediate CD3+cells decreased in response to ovariectomy, an effect that was countered by estrogen administration. These results suggest that the activation of extrathymic T cells may be regulated by physiological levels of estrogen.