A: Parental XG-6 cells, XG-6GFP or XG6Mcl-1 cells were starved of IL-6 for 1 hour and cultured without cytokine or with 2 ng/mL IL-6. At various days of culture, cells were harvested and apoptotic cells were detected with annexin-V staining. Results are those of one experiment representative of five.
B: The experiment described in A was performed on five occasions with XG-1 and XG-6 cells. Results are the mean values ± SD of apoptotic cells (expressed as the percentage of the maximum observed with XG-6 or XG-1 cells cultured without IL-6) on day 3 of culture. The statistical significance was determined using a Student t test for pairs.