Figure 4.

Characterization of vaccine-induced immune protective responses. Five- to six-week-old B6 WT mice were immunized with 100 μg of pVAX or 50 μg of each vaccine plasmid in 2 doses, with a fifteen-day interval between doses. The immunization regimen and the investigative approach are schematically represented in (A). At day 30, mice were either submitted to ELISPOT analysis for IFN-γ production (n = 6) (B) or challenged with 1 × 10² PFU of JHA1 (n = 10). Five days after challenge, the numbers of brain-infiltrating mononuclear cells were assessed (C), and the production of IL-10, IL-6, TNF, and IFN-γ was quantified in the supernatant of brain-infiltrating mononuclear cells (D) or splenocytes (E) after stimulation with a pool of DENV2-derived peptides. The percent survival after challenge was monitored for 15 days (F). The data were analyzed by a nonparametric Mann-Whitney test or by two-way ANOVA followed by Bonferroni's multiple comparisons test, where **p < 0.01, ***p < 0.001, and ****p < 0.0001. Survival curves were compared using the log-rank test.