Changes of inhibitory receptors on NK-92 cells and HLA-G on BeWo cells with Toxoplasma gondii infection.

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.