Background: The present study aimed to investigate the immunomodulatory activity of molecules secreted by decidual cells on dendritic cells (DCs) function in abortion-prone compared with non-abortion-prone mice.

Materials and Methods: The decidual cell supernatants (DS) were obtained from abortion and non-abortion mouse models. DCs were purified from CBA/J mice spleens and treated with antigen and DS. Treated DCs were injected into mice palms. After 5 days, draining lymph nodes were removed, cultured in the presence of cognate antigen, and proliferation of lymphocyte cells was measured by 3H-thymidin incorporation.

Results: Our results showed that immunosuppressive activity of DS from non-abortion-prone mice significantly decrease dendritic cells' ability to stimulate lymphocytes proliferation compared with DS from abortion-prone mice (Simulation index (SI) of 4.93 ± 0.34 versus 11.84 ± 0.79).We, also found that DS prepared from non-resorption sites compared with DS from resorption sites in abortion-prone mice had increased immunosuppressive activity on DC function (SI of 7.31 ± 1.02 versus 2.67 ± 0.49).

Conclusion: Due to our results, we concluded that immunomodulatory activity of molecules secreted within decidual tissue is different between abortion-prone and non-abortion-prone mice. Based on the key role of DCs in inducing fetomaternal tolerance, we claimed that these molecules, through modulation of DCs function, play crucial role on pregnancy outcome.