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The aim of this study were to demonstrate the effects of Yellow fluorescent protein- Toxoplasma gondii infection on the NK-92 cells co-cultured with BeWo cells in vitro and to verify the implications upon adverse pregnancy outcome. There are four groups including NK-92 cells infected or uninfected with T. gondii, and NK-92 cells co-cultured with BeWo cells in the presence or absent of T. gondii infection. Cells were observed by fluorescence microscope at 12, 24, 36, 48, and 60 h after infection. Levels of inhibitory receptors killer immunoglobulin-like receptor (KIR)2DL4 and ILT-2 expressed on NK-92 cells, and their common ligand HLA-G expressed on BeWo cells were measured by real-time PCR and flow cytometry in all groups. Levels of KIR2DL4, ILT-2 and HLA-G increased at 12, 24, 36, and 48 h, while decreased at 60 h in all T. gondii-infected groups compared with their parallel control groups, respectively. KIR2DL4 and ILT-2 expression in co-culture groups with infection were higher than those in infected NK-92 groups at 12, 24, 36, and 48 h, while there were no significant differences at 60 h. The expression of the two inhibitory receptors was correlated with HLA-G expression in infected co-culture groups. The changes of inhibitory receptors on NK-92 cells and their common ligand HLA-G on BeWo cells with T. gondii infection might contribute to the occurrence of adverse pregnancy outcome. [ABSTRACT FROM AUTHOR]

Objective: To investigate the changes of human decidual natural killer (dNK) cells cocultured with Toxoplasma gondii in vitro and to infer implications on pregnancy. Design: Case-control study. Setting: College and hospital. Patient(s): Decidual tissue was obtained from 85 patients undergoing voluntary abortion during the first trimester of gestation (6–12 weeks). Intervention(s): None. Main Outcome Measure(s): The dNK cells were isolated and infected with YFP-Toxoplasma gondii. Cells were observed by fluorescence and confocal microscopy. The CD56brightCD16−/CD56dimCD16+ dNK ratio, expression of KIR2DL4, ILT-2, and NKG2D on dNK cells were analyzed by flow cytometry and the cytotoxic activity of infected dNK cells were evaluated. Result(s): The CD56dimCD16+/CD56brightCD16− dNK ratio was significantly elevated at 12, 24, and 48 hours after YFP-T. gondii infection. Expression of KIR2DL4, ILT-2, and NKG2D were increased after infection, but NKG2D were significantly higher than those of KIR2DL4 and ILT-2. Both the CD56dimCD16+/CD56brightCD16− dNK ratio and NKG2D expression were correlated with dNK cytotoxic activity. Conclusion(s): Enhanced dNK cytotoxicity due to increased CD16 and NKG2D expression may contribute to abnormal pregnancy outcomes observed with maternal infection with T. gondii. [ABSTRACT FROM AUTHOR]