Figure 2.

T cell E-derived peptide identification in pE1D2-immunized BALB/c mice by IFN-γ ELISPOT assays. Schematic timeline representation of the experiment (A). Splenocytes isolated from pE1D2-immunized BALB/c mice (n = 3, pooled), challenged or not with a neuroadapted DENV2 strain (NGC), were stimulated with E-derived peptides for 18 h, and the number of cells producing IFN-γ was measured by ELISPOT assay. Peptides and cells were evaluated in pools (B) and positive peptides were confirmed by tests performed with cells from individual mice (n = 5) (C). ELISPOT assays were performed using splenocytes collected 15 days following DNA inoculation (gray and light green bars/dots) or 21 (B) and 7 days post-infection (C) (dark green bars/dots). Cells from naïve or pcTPA-inoculated mice were used as negative controls (B,C). The horizontal dotted lines represent the cut-off selection point (≥5 SFC/5 × 10⁵ cells) (B). Bars represent the mean plus standard deviation of triplicate data in (B) and the means of each group in (C). Symbols represent significant differences between groups, using non-parametric two-tailed Mann-Whitney statistical tests: * pcTPA- vs. pE1D2-inoculated mice; # naïve animals vs. pE1D2-immunized mice after DENV2 challenge; + pE1D2-immunized mice vs. pE1D2-immunized animals after DENV2 challenge; Φ naïve animals vs. DENV2 challenged mice; λ pE1D2-immunized mice vs. DENV2 challenged animals; Ψ pE1D2-immunized animals challenged with DENV2 vs. DENV2 challenged mice. One symbol: p < 0.05; two symbols: p < 0.001; three symbols: p < 0.0001.