Lymphocytes and MHC class II positive cells in the female rabbit reproductive tract before and after ovulation

In this study, we identified lymphocytes and MHC class II positive (MHC-II+) cells in the reproductive tract of female rabbits both before and after ovulation. CD43+ T cells were frequently present in the mucosa of the oviduct, cervix, and vagina, but far fewer positive cells were seen in the endometrium. The induction of ovulation did not change the cell density in these regions. KEN-5+ T cells and MHC-II+ cells were also frequently seen in the mucosa of the oviduct, cervix, and vagina both before and after ovulation. However, in the uterus, there were very few positive cells before ovulation, but the number increased dramatically after ovulation. Associated with the increase of KEN-5+ T cells, IL-2 mRNA expression in the uterus also increased after ovulation, suggesting that the uterus experienced an increase of T-cell activation. IgM- and IgA-positive B cells were not commonly seen in the reproductive tract and the induction of ovulation did not alter this. Our results suggest that the reproductive tract of female rabbits has the capacity to mount an immune response and that the immune cell distribution of the rabbit reproductive tract has some distinctive features compared with that found in other species.