Treatment with CpG-ODN inhibited the expression of FasL in HepG2 cells in a dose- and time-dependent manner. (A) Dose effect. HepG2 cells were treated with different concentrations of CpG-ODN for 48 h. (B) Time effect. HepG2 cells were treated with 1 μM CpG-ODN for the indicated time periods. The cells were harvested, and the frequency of FasL-positive cells was determined by FACS analysis. Data are expressed as mean% ± SEM of each group of the cells from four independent experiments. *p < 0.05 vs. controls.