Predominant Th2-type response during normal pregnancy of rats

The immunological parameters were analyzed during pregnancy of Lewis rats by the methods of flow cytometry, thymidine incorporation and enzyme-linked immunospot (ELISPOT). MHC II of spleen mononuclear cells (MNCs) and CD11c of periphery blood MNCs was apparently downregulated in late pregnancy, while the costimulatory molecules B7-1 and B7-2 showed no difference. Increased expression of Th2 cytokines (IL-10, IL-4) and TGFbeta was detected in the spleen and peripheral blood MNCs in the third trimester by flow cytometry. No suppression of Th1 cytokine represented by IFNgamma was found. Furthermore, antigen specific proliferation of spleen and peripheral blood MNCs was unchanged, but higher proliferation of MNCs from mesenteric lymph nodes was shown in late pregnancy. There was an inhibition of antigen specific antibody production in pregnancy examined by ELISPOT. These data indicate the immunomodulatory effects of sex-hormones in pregnancy, which may be related to the remission of T cell-mediated autoimmune diseases during pregnancy.