Figure 3.
Evaluation of the generation of a protective immune memory response after SFV-IL-12 + anti-CD137 treatment and efficacy in the B16.F10 model. (a) Survivor mice from experiments shown in Figures 1a and 2 were rechallenged in a first step with 5 × 105 B16-OVA cells at day 112 and in a second step with 5 × 105 B16.F10 cells at day 203. When indicated, a group of naive animals were inoculated with the same tumor cells to control each rechallenge experiment. Mice survival was monitored and analyzed by sequential Kaplan–Meier plots. The different groups were compared with the log-rank test. (b) C57BL/6 female mice were inoculated in the flank with 5 × 105 B16.F10 cells on day 0 and then received an intratumoral injection of saline or 107 viral particles (vp) of SFV-IL-12 on day 7. On days 7, 10, and 14 mice received intraperitoneally 100 µg of anti-CD137 mAb as indicated in the figure. (c) Kaplan–Meier plot of mouse survival. The SFV-IL-12 + anti-CD137-treated group was compared with the rest of the groups with the log-rank test. n.s., not significant; *P < 0.05; **P < 0.01. α, anti-; SFV-IL-12, Semliki Forest virus encoding interleukin-12.