Microenvironment of the feto–maternal interface protects the semiallogenic fetus through its immunomodulatory activity on dendritic cells

ObjectiveTo investigate the immunomodulatory activity of decidual culture supernatant on dendritic cell (DC) functions.DesignIn vivo and in vitro experimental study using mice.SettingAcademic research laboratory.Animal(s)C57BL/6-mated female Balb/c mice.Intervention(s)Culture supernatants of decidual cells obtained from the uteri of allogenic pregnant mice (Balb/c × C57BL/6) were collected. Dendritic cells were purified from Balb/c mice spleens and pulsed with antigen during overnight culture. In some cultures, decidual supernatant was added at 5%, 10%, or 20% final concentration. Endometrial culture supernatant-treated DCs served as a control. Antigen-pulsed DCs were injected into the front footpads of syngeneic mice.Main Outcome Measure(s)Lymph nodes of primed mice were removed 5 days after DC injection. Antigen-specific proliferation and interleukin-10 and interferon gamma production by lymphocytes were measured by 3H-Thymidine incorporation and ELISA, respectively.Result(s)The results showed that decidual culture supernatant markedly blocked in vivo antigen presentation by DCs and inhibited their capacity to induce interferon gamma (but not interleukin-10) production by primed lymphocytes.Conclusion(s)It seems that soluble factors produced by decidual cells are important mediators of immunoregulation at the feto–maternal interface, which provide the two fundamental requirements for protection of the semiallogenic fetus, namely immunologic tolerance and predominance of T helper 2 immunity, through modulation of DCs function.