Background: Pregnancy is a unique immunologic phenomenon in that despite expressing antigens with paternal origin of the embryos the interaction between maternal immune cells and fetal ones not only does not cause damage to the fetus, is necessary for fetal development . Since immune cell function is essential in the success of pregnancy and many of spontaneous abortions are associated with immunological defects. Understanding immune cells recognition, their distribution in the uterine tissue and the immune mechanisms involved in creating natural tolerance to an allograft (embryos), are necessary .

  Methods : In this descriptive-analytic study distribution of various immune cells in the spleen and uterine tissue in pregnant mice was evaluated by immunohistochemical staining using monoclonal antibody, HRP enzyme, Alkaline phosphates and eventually the emergence of color on the cells was determined.

  Results: The results of immunohistochemical staining with different antibodies showed that there are significant difference between the two tissues, spleen and uterus of the cell population CD11c+, CD11b+, CD86 + and MHC-II+ . The immune cells in different zones of the spleen and uterine tissue are different

  Conclusions: Different distribution pattern of immune cells in the uterus and spleen tissue showed the importance and role of mucosal immune in protection of the fetus in the uterus and promotion of a successful pregnancy. Also, the presence of immune cells in certain areas prevents the destructive immune response against the fetus. And different dispersion pattern of immune cells is in proportion with function cells in pregnancy.