Differential effect of IFN-tau on proliferation and distribution of lymphocyte subsets in one-way mixed lymphocyte reaction in cows and heifers.

IFN-tau is a signaling protein secreted by the bovine conceptus during the peri-implantation period and responsible for pregnancy recognition. Its main role is the prevention of pulsatile release of luteolytic PGF2alpha, but it also exerts immunomodulatory activities characteristic for other type I interferons. The aim of the study was to examine the effect of IFN-tau on the proliferation and distribution of peripheral blood lymphocyte subsets during one-way mixed lymphocyte reaction (MLR) in cows and heifers. IFN-tau inhibited the proliferative response of lymphocytes in MLR both in cows and heifers in a dose-dependent manner, but cow lymphocytes were less susceptible than those ones from heifers. It was also showed that IFN-tau differentially changed lymphocyte subsets distribution in MLR in cows and heifers. In cows, the relative percentage of CD8(+) cells after MRL in the presence of IFN-tau was significantly lower than in heifers. Differential effect of rIFN-tau on proliferation and lymphocyte subsets distribution in a one-way MRL in cows and heifers indicated that the age of the mother is an important factor in immunomodulatory effect towards developing bovine embryo.