Importantly, investigation of the cellular immune dysregulation showed that macrophages, not uNK cells, were activated to produce TNF-α and infiltrate the placental zone.35 Taken together, these results demonstrate that in response to certain pathogens,

IL-10 is a protective agent. Furthermore, the absence of IL-10 allows investigation of the pathogenesis of bacterial and viral motifs at sub-clinical click here levels. On the other hand, as a simple rule of nature, IL-10 cannot be presented as a global suppressive agent against all infectious agents. Our recent results are intriguing in that IL-10 does not protect pregnancy against mimics which represent double stranded RNA viruses (unpublished observations). T regulatory (Tregs) cells in the decidua have recently come under the microscope of pregnancy research. Their characteristic ability to produce suppressive cytokines in response to foreign antigen makes Tregs promising therapeutic targets for intervention toward adverse pregnancy outcomes. Tregs are characterized as CD4+/CD25+/Foxp3+, and their ability to produce IL-10 is well documented.36 The presence of Tregs was assessed in the murine decidua. Unpublished data from our laboratory and others show that murine Tregs appear in the estrous cycle and increase early in pregnancy, peaking on gd10–12 and declining thereafter.37,38 Spontaneous fetal resorption in abortion prone CBA×DBA/2

mice can be abrogated by adoptive transfer of Tregs harvested from same gestational age WT mice. Importantly, neutralization of IL-10 in the aforementioned experimental setting abolishes the ability of WT Tregs to rescue CBA×DBA/2 fetal resorption.39 much Birinapant Finally, recent observations in humans have shown that decidual Tregs can inhibit immune stimulation of conventional T cells through cell-cell contact or IL-10 production.40 Recent findings

suggest that uterine Tregs may be of peripheral blood origin and their development toward the uterine phenotype may be under hormonal control.41 Migration studies with human decidual Tregs show that Tregs migrate to areas of hCG production. Women with ectopic pregnancies or spontaneous abortion show decreased IL-10 production coupled to low levels of Treg migration to trophoblast/hCG+ dense regions.42 Interestingly, murine CD4+/CD25− cells treated with E2 were converted to Foxp3+ T cells that produced IL-10, lending further evidence that Tregs may be under hormonal control.43 However, one study posits that decidual Treg development may be driven in part by the presence of paternal antigen as pseudopregnant females (mated with vasectomized males) showed increased levels of decidual Tregs.44 Unpublished data from our laboratory show that Treg numbers do not differ between WT and IL-10 null pregnancies over the spectrum of gestation. However, we have begun to address differences in functionality of Tregs from IL-10−/− versus WT mice.