| Abstract: | T cells are the dominant lymphocytes in the endometrium and are considered to play acrucial role in implantation and in the maintenance of gestation through cytokineproduction and immune regulation. The mechanisms underlying immunoregulation at thefeto-maternal interface are still obscure for this complex system. Understanding therole of T cells is a key factor in understanding the endometrial immune system. Inthis study, the distribution of endometrial CD3+ T cells in bovines wasexamined by immunohistochemical analysis. The estrous cycle and gestation was dividedinto 4 stages, and the number of CD3+-positive T cells was counted in eachstage. CD3+ cells were found in the endometrium in significant numbersthroughout the estrous cycle and were mostly located in the subepithelial area. Thenumber of CD3+ cells significantly increased in the early and mid-lutealphases but decreased after implantation with the progression of gestation. No T cellswere found in the placentome or specifically in the tissues near the fetus, includingthe trophoblastic area. In addition, very few T cells were found in stromal regionsclose to the myometrium of the endometrium. These findings suggest thatdownregulation of bovine endometrial CD3+ T-cell functions is closelyrelated to the successful maintenance of gestation in a spatiotemporal manner. |
