EFFECTS OF INTERFERON-TAU AND INTERFERON-ALPHA ON PROLIFERATION OF BOVINE ENDOMETRIAL CELLS

The ruminant conceptus secretes a unique interferon, interferon-tau, t hat regulates endometrial prostaglandin secretion during early pregnan cy. Because one of the pleiotropic effects of interferons is to inhibi t cellular proliferation, a series of experiments was conducted to det ermine whether or not the bovine endometrium is sensitive to the antip roliferative effect of interferon-tau and the related interferon, inte rferon-alpha. Endometrial epithelial and stromal cells were prepared f rom the endometrium of cows from Days 11-17 after estrus and incubated with recombinant bovine interferon-tau (rbIFN tau; 1-1000 ng/ml), rec ombinant bovine interferon-alpha 1 (rblFN alpha; 1-1000 ng/ml), recomb inant human interferon-alpha 2b (rhIFN alpha; 100 ng/ml), or ovine int erferon-tau (oIFN tau; 100 ng/ml). Proliferation was determined by mon itoring uptake of [H-3]thymidine into DNA. Generally, interferons did not inhibit proliferation of endometrial epithelial cells. Exceptions were for 1000 ng/ml rbIFN tau, which inhibited proliferation by 23%; 1 00 ng/ml rbIFN alpha, which inhibited proliferation by 28% in one of t wo experiments only; and 100 ng/ml oIFN tau, which inhibited prolifera tion by 17%. Proliferation of endometrial stromal cells was not inhibi ted by any concentration of any Interferon in two separate experiments . Therefore, unlike other bovine cells tested previously (lymphocytes and oviductal cells), bovine endometrial cells were not consistently i nhibited by IFN tau or IFN alpha, Such reduced responsiveness of endom etrial cells to the antiproliferative effects of type I interferons co uld allow for growth of the endometrium during the period of pregnancy when the conceptus produces IFN tau.