Figure 6.

SCR-Deleted EEV Maintains Oncolytic Activity In Vivo in the Presence of Vaccinia-Neutralizing Antibodies

(A) In vivo bioluminescence imaging of tumor burden and viral replication. Athymic nude mice with peritoneal dissemination of A2780 cells expressing Rluc were inoculated with 100 μL rabbit anti-VV-immunized serum (IgG fraction) before intraperitoneal injection of B5R EEV or ΔSCR EEV derived from the supernatant of infected A2780 cells. Tumor Rluc was detected on days −3 and 8, and viral Fluc was detected on days 3 and 7 after virus injection (n = 6). (B) Quantification of viral Fluc luminescence after virus injection. Solid and dashed lines represent serum (IgG)-treated and untreated cells, respectively. *p < 0.05 (two-way ANOVA). (C) Quantification of tumor Rluc luminescence before and after virus injection. Data in (B) and (C) are presented as means ± SD (n = 6). *p < 0.05 (two-way ANOVA). (D) Survival curves of mice in (A)–(C) generated by Kaplan-Meier analysis. Treatment with ΔSCR EEV + αVV Ab (IgG) prolonged survival compared to PBS + αVV Ab (p = 0.0005, log rank test) and B5R EEV + αVV Ab (p = 0.0291, log rank test).