Induction of CTL activities in mice with complete regression was observed after gene therapy with IL-12, IL-12/pro-IL-18, or IL-12/pro-IL-18/ICE. The representative data of two independent experiments are shown. □, IL-12 cDNA; ▵, IL-12/pro-IL-18 cDNA; ●, IL-12/pro-IL-18/ICE cDNA; ○, control plasmid (pNGVL-3).