IL-6 protects against anti-fas. 8226 cells (▨) or UCLA #1 cells (□) cultured in anti-fas (AF, 0.5 μg/mL) alone for 20 hours, or anti-fas + IL-6 (1,000 U/mL). As shown in the figure, the IL-6 was present for either 15, 30, 60, or 120 minutes before addition of anti-fas. Results are the percent apoptosis from DAPI-stained cytospins, mean ± SD of three separate experiments. 8226 cells cultured in media alone for 20 hours showed only 3.5% apoptosis in this assay. Above each bar is shown the mean percent viability (from dye exclusion assays of the three experiments). 8226 cells cultured in media alone for 20 hours showed a viability of 88%. Only the presence of IL-6 for 60 or 120 minutes significantly (P < .05) decreased the % apoptosis and increased the percent viability relative to the cells cultured in anti-fasalone.