Raji cells were treated with 5-aza-2′-deoxycytidine in 3 experiments to demethylate the DAP-Kinase CpG island and then exposed to γ interferon. (A) Raji cell apoptosis. Raji cells were treated with 1 μmol/L 5-aza-2′-deoxycytidine for 5 days and then with 1,000 U/mL γ interferon for 7 days. Cells were analyzed for apoptosis on days 3, 5, and 7 of γ inteferon or carrier control treatment. By day 7, Raji cells exposed to γ interferon were undergoing more apoptosis than Raji cells exposed only to carrier control. (B) Raji cell apoptosis. Raji cells were treated with 0.5 μmol/L 5-aza-2′-deoxycytidine for 5 days and then with 1,000 U/mL γ interferon for 7 days. Cells were analyzed for apoptosis on days 3, 5, and 7 of γ inteferon or carrier control treatment. By day 7, Raji cells exposed to γ interferon were undergoing more apoptosis than Raji cells exposed only to carrier control. (C) Raji cell apoptosis. Raji cells were treated with 0.5 μmol/L 5-aza-2′-deoxycytidine for 2 days and then with 1,000 U/mL γ interferon for 7 days. Cells were analyzed for apoptosis on days 3, 5, and 7 of γ inteferon or carrier control treatment. By day 5, a trend had developed in which Raji cells exposed to γ interferon underwent more apoptosis than those exposed with carrier control alone.