Abstract:To explore the invasive ability of Toxoplasma gondii to the cultured cell lines and to induce apoptosis in these cells, human umbilical venous endothelial cells (HUVEC), Vero cells, J774A.1 cells and THP-1 cells were employed as the test cells, and the power of invasions of T.gondii into these cell lines was observed after Giemsa staining and under electron microscopy. Flow cytometry was used to investigate the apoptosis in these cells induced by T.gondii. It was demonstrated that T.gondii could invade these 4 types of cells with formation of parasitophorous vacuoles.The invasive ratios to J744A and THP-1 cells were higher than those of HUVEC and Vero cells, and the cytoskeleton inhibitor cytochalasin D could significantly reduce the invasive ratios of J744A and THP-1 cells. Different degrees of apoptosis or necrosis in HUVEC and J744A cells induced by T.gondii could be observed, mainly with apoptosis in HUVEC cells but necrosis in J744A cells.It was also evident that the difference in cell type could greatly influence the development of apoptosis or necrosis in these cell lines after induction with T.gondii.It is concluded that through different mechanisms, T. gondii can invade into various cell types, including phagocytic and non-phagocytic cells.
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