Fig. 2

Different T. gondii strains at multiple MOIs inhibit activation of the NF-κB promoter. a pNF-κB-Luc and pTL-TK plasmids were co-intransfected into HEK293T cells followed by no treatment (blank) or infected with T. gondii RHΔHX. Six hours later, newly egressed tachyzoites were harvested, counted and added into the HEK293T cells as indicated. Eighteen hours post-infection, human recombinant TNF-α was added at a final concentration of 20 ng/ml and lasted for 6 h, and TNF-α was not added to the control (Ctrl). Twenty-four hours post-infection, cells were collected, lysed and luciferase activities were measured as recommended. The results of luciferase activity in each sample are presented as the average of three independent experiments. b Toxoplasma gondii strains from Me49 cannot inhibit activation of the NF-κB promoter. The results of luciferase activity in each sample are presented as the average of three independent experiments (^**P < 0.01)