Figure 4.

Fusion to human invariant chain (hIi) improves magnitude and breadth of nonstructural (NS)-specific T-cell response and CD8⁺ T cells frequency in nonhuman primates (NHPs). Cynomolgus macaques were immunized with ChAd3NS or ChAd3hIiNS at 10¹⁰ vp dose. T-cell response was measured in peripheral blood mononuclear cells (PBMCs) 4 weeks after vaccination by means of interferon-γ (IFN-γ) enzyme-linked immunosorbent spot (ELISpot) and intracellular cytokine staining (ICS). (a) Magnitude and breadth of ELISpot response. Each bar shows individual NHP response to dimethyl sulfoxide (DMSO) and to each of the six genotype 1b peptide pools irrespective of whether it is positive or negative, as shown in the graph's legend. Below each bar, the number of positive pools, according to ELISpot positivity criteria defined in Materials and Methods (≥50 spot-forming cells (SFCs)/million PBMCs to at least one peptide pool; ≥ three times of DMSO background), recognized in individual NHPs are shown. Data are expressed as IFN-γ SFCs per million PBMCs. (b) Frequencies of IFN-γ–secreting cells analyzed by ICS, expressed as the percentage of NS-specific CD4⁺ (open symbols) or CD8⁺ (filled symbols) response over total CD4⁺ or CD8⁺ in individual animals. Lines represent geometric mean (filled for CD8 and dashed for CD4).