Figure 2.

ChAdOx1/MVA P1A vaccination exhibits good therapeutic efficacy against early established 15V4T3 tumors. (A) DBA/2 mice were implanted with 1x10⁶ 15V4T3 cells via subcutaneous (s.c.) injection. Five days after tumor implantation, mice were vaccinated with ChAdOx1-Ii-P1A and MVA-P1A according to the schedules shown and indicated doses of virus: ChAd^high - 10⁸ IU, ChAd^low - 10⁷ IU, MVA^high - 10⁷ PFU and MVA^low - 10⁶ PFU. Tumor growth was followed for 50 days and mice culled when tumors reached 12 mm in any direction. (B-D) Mean tumor growth (B), survival (C) and individual tumor growth (D) for each group are shown. (E) Tumor size on day 20 post implantation was correlated with the frequency of blood IFN-γ⁺ CD8⁺ T cells detected by ex vivo P1A peptide stimulation and ICS on day 23. Tumor growth data are presented as mean tumor volume (mm³) ± SEM. Each group contained 6-7 mice, with data representative of 2 independent experiments. Statistically significant differences between groups were determined by a two-way ANOVA with Tukey’s post hoc test for tumor volume data and a log-rank test for survival data. Statistical differences are shown only between vaccinated groups and ChAdOx/MVA control group. Significance of correlation was determined through a Spearman rank test. ***, p ≤ 0.001 ****, p ≤ 0.0001.