Bovine luteal cells express class I and II major histocompatibility complex molecules and stimulate T lymphocyte proliferation in vitro. Proliferation of T lymphocytes is greater in cocultures of luteal cells and T lymphocytes collected following administration of a luteolytic dose of prostaglandin (PG) F2α to the cow. Whether this results from changes in luteal cells that increase their ability to stimulate T lymphocyte proliferation or from changes in T lymphocytes that enhance their ability to respond to luteal cells is unclear. To determine which is the case, luteal cell-T lymphocyte cocultures were performed using luteal cells and T lymphocytes isolated from the same animals before and 8 h after administration of PGF2α. In the presence of T lymphocytes collected before PGF2α administration, luteal cells isolated after PGF2α were more potent stimulators of T lymphocyte proliferation than were luteal cells collected before PGF2α (P < 0.05). The effect of progesterone on luteal cell-stimulated T lymphocyte proliferation was also evaluated. Proliferation of T lymphocytes was greater (P < 0.05) in cultures containing the cytochrome P450 side-chain cleavage enzyme-inhibitor aminoglutethimide. Exogenous progesterone caused a dose-dependent inhibition of luteal cell-stimulated T lymphocyte proliferation (P < 0.05). Progesterone-receptor mRNA was undetectable in peripheral blood mononuclear cells collected before and after PGF2α administration, indicating that the effect of progesterone was not mediated via progesterone receptors in lymphocytes. These results imply that specific changes in luteal cells in response to PGF2α enhance the ability of these cells to stimulate T lymphocyte proliferation. These results also demonstrate that progesterone can suppress luteal cell-stimulated T lymphocyte proliferation.
All Science Journal Classification (ASJC) codes
- Cell Biology