Figure 1.

Fusion of nonstructural (NS) antigen to murine invariant chain (mIi) enhances magnitude and breadth of T-cell response in CD1 mice after priming with ChAd3. CD1 mice were vaccinated with ChAd3NS or ChAd3mIiNS with 10⁸ viral particles (vp) dose, and T-cell response was tested on splenocytes 2 weeks later. (a) Cross-reactivity of T-cell responses, measured by interferon-γ (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) using two comparable sets of six 15-mer peptide pools spanning NS3-5B polyprotein of either hepatitis C virus (HCV) genotype 1b (corresponding to the vaccine sequence) or 3a. Vaccines received and pools' genotypes are indicated at the bottom of the graph. Each symbol represents the total NS response in individual mice, defined as the sum of responses to the six peptide pools less the dimethyl sulfoxide (DMSO) background and expressed as spot-forming cells (SFCs) per million splenocytes. Lines represent geometric mean (GM). (b) Correlation of total NS ELISpot response to genotype 1b or 3a peptide pools in individual mice. Open and filled symbols correspond to animals vaccinated with ChAd3NS and ChAd3mIiNS, respectively. (c) Magnitude and breadth of ELISpot response. Each bar shows individual mouse response to DMSO and to each of the six 15-mer peptide pools, irrespective of whether it is positive or negative, spanning the entire NS3-5B polyprotein length (genotype 1b), as shown in the graph's legend. Data are expressed as IFN-γ SFCs/million splenocytes. (d) Breadth analysis in ChAd3NS- and ChAd3mIiNS-vaccinated mice. Each symbol corresponds to the number of positive pools, according to ELISpot positivity criteria defined in Materials and Methods, recognized in individual mice. Lines represent the group median. (e) Frequencies of IFN-γ–secreting cells analyzed by intracellular staining, expressed as the percentage of NS-specific CD4⁺ (open symbols) or CD8⁺ (filled symbols) response over total CD4⁺ or CD8⁺. Lines represent GM (filled for CD8 and dashed for CD4).