CpG-ODN treatment suppressed the caspase-3 activation in Jurkat cells. HepG2 and Jurkat cells were cultured in medium alone or treated with 1 μM CpG-ODN, respectively for 24 h. The unmanipulated HepG2 and Jurkat cells or the CpG-ODN-treated HepG2 and Jurkat cells were co-cultured for 24, respectively. The Jurkat cells were harvested and the contents of activated caspase-3 were determined by flow cytometry analysis. (A) The unmanipulated Jurkat cells; (B) The CpG-ODN-treated Jurkat cells. Data shown are representative histograms from each group of cells from four separate experiments. The percentage of positive cells was indicated.