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Inhibitory receptors and activating receptor expressed on decidual natural killer (dNK) cells are generally believed to be important in abnormal pregnancy outcomes and induced adverse pregnancy. However, if Toxoplasma gondii (T. gondii) infection induced abnormal pregnancy was related to dNK cells changes is not clear. In this study, we used human dNK cells co-cultured with human extravillous cytotrophoblast (EVT) cells following YFP-Toxoplasma gondii (YFP-T. gondii) infection in vitro and established animal pregnant infection model. Levels of inhibitory receptors KIR2DL4 and ILT-2, their ligand HLA-G, and activating receptor NKG2D in human decidua, and NKG2A and its ligand Qa-1 and NKG2D in mice uterine were analyzed by real-time PCR and flow cytometry with levels of NKG2D significantly higher than those of KIR2DL4 and ILT-2 in vitro and in invo. The level of NKG2D was positively correlated with cytotoxic activity of dNK cells in vitro. Numbers of abnormal pregnancies were significantly greater in the infected group than in the control group. This result demonstrated that the increased NKG2D expression and imbalance between inhibitory receptors of dNK cells and HLA-G may contribute to abnormal pregnancy outcomes observed upon maternal infection with T. gondii. [ABSTRACT FROM AUTHOR]

Aims: Toinvestigate the immunoprotective effect of IL-10 on pregnancy in Toxoplasma gondii-infected C57BL/6 mice. Methods: Twenty-four pregnant mice were randomly divided into 3 equal groups, i.e. a control group (CG), an infected group (IG) and an infected group treated with IL-10 (IPTG). Each IPTG and IG mouse was infected with 400 T. gondii trophozoites on gestational day (GD) 8. Each IPTG mouse was injected with 1 μg recombinant mouse IL-10 via a tail vein on GD 10 and 12. The mice were sacrificed on day 7 postinfection. Qa-1 and NKG2A were analyzed in the placenta by flow cytometry and real-time PCR. IL-4, IL-10 and IFN-γ in the placenta supernatant were analyzed by ELISA. Statistical analysis was performed by one-way ANOVA. Results: IPTG mice showed a better mental state, had larger fetuses and placentas with a better blood supply and a lower resorption ratio compared to IG mice. NKG2A and Qa-1 were significantly increased in IPTG mice compared to IG mice (p < 0.05). IL-4 and IL-10 in IPTG placenta supernatant were increased (p < 0.05), but IFN-γ was decreased (p < 0.05) compared to IG placenta supernatant. The ratios of IFN-γ/IL-4 and IFN-γ/IL-10 were decreased in IPTG mice compared to IG mice (p < 0.05, p < 0.05). Conclusion: IL-10 plays an immunoprotective role and improves the pregnancy outcome of T. gondii-infected mice. Copyright © 2011 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]