Figure 7. Orthotopic glioma model with intracranial injection of RRV-scFv-PDL1 demonstrates a dose-dependent anti-tumor activity.

(A) Female B6C3F1 mice (8-week-old; n = 10 per group) were i.c. implanted with 1 × 10⁴ of Tu-2449 cells. Survival analysis was monitored for 90 days. Mice in the experimental groups were injected with 1E5 or 1E6 TU of purified RRV-scFv-PDL1 vector on day 4 post tumor implant. Control groups are mice bearing 100% pre-transduced scFv PD-L1 expressing tumor cells (100% scFv) and mice treated anti-PD-1 antibody (Naive + αPD-1) or isotype control (Naive + Isotype), (300 µg per mouse i.p. induction on day 4; 200 µg per mouse maintenance dose on day 10, 14 and 17 indicated by black arrows). Survival data were plotted by the Kaplan–Meier method. Statistical significance of survival between mice treated with anti-PD-1 antibody and injection-treated RRVscFvPDL1 mice was determined by the Log-rank (Mantel-Cox) test, ^*p = 0.0045. (B) Mice which had survived from initial tumor implant from RRV-scFv-PDL1 pre-transduced or injectiontreated groups were challenged with 2 × 10⁶ Tu-2449SC cells on the right flank on day 80 (red arrow) post primary tumor implant. Tumor growth and measurement were monitored over time. Statistical significance was determined by 2-way ANOVA of the following data sets: ^*p < 0.0001 for Naive vs 1E6 TU RRV-scFv PD-L1. Error bars indicate the SEM of the dataset.