Abstract: The study on how to get culture supernatants of Toxoplasma gondii and investigate the inhibitive effects of culture supernatants of Toxoplasma gondii on the proliferation and on the cell cycle of Human acute monocytic leukemia cell line THP-1 in vitro. Methods THP-1 cells (concentration of 5×104mL-1) were harvested in the different cell culture plates. The cells were treated for different hours with different concentrations of Toxoplasma gondii culture supernatant. Growth inhibition rates were tested with the MTT method；Cell cycle were checked by Flow Cytometer. Western blot was used to detect the leves of NF-κB/p65 and cyclin D1 of cells. Results the culture supernatants of Toxoplasma gondii could inhibit the proliferation of THP-1 cells in a time-dose dependent manner. Cell cycle was significantly stopped at G0/G1phase by the culture supernatants with FCM technology. The culture supernatant of Toxoplasma gondii reduced the expressions of gene NF-κB 、cyclin D1 of THP-1 cells. Conclusion The culture supernatant of Toxoplasma gondii may inhibit THP-1 cell and arrest the cell cycle of THP-1 cells at G0/G1phase mainly by regulating the expression of gene NF-κB 、cyclin D1 .

Key words: Culture supernatants of Toxoplasma gondii, Human acute monocytic leukemia cell line THP-1, Cell cycle