Figure 4.

Frequencies and functional characterization of antigen-specific cytokine producing T-cells from HCV p7 protein or p7 pepmix (H77) vaccinated mice after surrogate challenge. Five days after challenge with p7(H77)-GFP plasmid, PBMCs (a,b) and liver cells (c,d) were isolated from individual mice, re-stimulated with a pool of overlapping p7(H77) peptides, and analyzed by multi-parameter IC-FACS to assess the frequencies of p7-specific IFN-γ, TNF-α and IL-2 producing CD44⁺ CD4⁺ T-cells (a,c) or CD44⁺ CD8⁺ T-cells (b,d) out of the total CD4⁺ or CD8⁺ T-cell population, respectively, 5 days after surrogate challenge. Pie charts show the distribution of IFN-γ producing CD44⁺ CD4⁺ or CD44⁺ CD8⁺ T-cells divided into three distinct subpopulations based on their ability to co-produce TNF-α alone or in combination with IL-2. Empty pies indicate total cytokine responses below a 0.2% cut-off. Data are shown as means and standard errors of the mean (SEM) (n = 7 to 12 mice in each vaccine group). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001.