Fig. 3: Intratumoral injection of VZV-vax or a gE-derived MHC-II-restricted peptide with polyI:C provides tumor control and long-term protection.

Experimental design: C57BL/6 mice were prime-boost immunized intramuscularly with the VZV vaccine prior to TC-1 tumor subcutaneous challenge one week after boost. When tumor reached a volume between 50 and 100 m³, mice were treated six times with saline, VZV-vax alone (1/40^th of the human dose) or the MHC-II-restricted gE_71-90 peptide (2 μg) admixed with polyI:C LMW (50 μg). Mice were monitored twice a week for (A) tumor growth and (B) survival. A Tumor growth is shown as the mean of tumor volume for each group and SE (n = 7 per group). Statistical analysis with Dunn’s test was performed for multiple comparison of tumor growth. B Survival comparisons were assessed by Mantel–Cox test (**P < 0.01, *P < 0.05). C Tumor-free mice from the VZV-vax and gE_71-90 + polyI:C-treated groups, and naïve mice were rechallenged with TC-1 cells, 60 days after the primary challenge and tumor growth was monitored twice a week until endpoint. D anti-VZV gE protein responses were measured by ELISA in plasma samples. Data are shown as individual values and geometric mean of the EC50 of IgG titer and 95% confidence interval. In a separate experiment, (E) IFN-γ, (F) TNF-α and (G) IL-2 production was assessed 36 h after the last IT treatment by intracellular staining of circulating CD4⁺ T cells after in vitro restimulation with VZV gE overlapping peptide library. Individual cytokine production is shown as individual values and mean percentage within CD44⁺CD4⁺T cells with SE. Statistical analysis was performed using Dunn’s test for multiple comparison between groups (*P < 0.05 **P < 0.01, ***P < 0.001, ****P < 0.0001, numeric values, ns = not significant) (n = 4 per group).