Recombinant IL-21 treatment leads to the rescue of HCV-specific CD8⁺ T cell responses.

<p>PBMCs from 7 chronically HCV monoinfected individuals and 10 HIV/HCV coinfected individuals were cultured in media alone or with recombinant human IL-21 (at 100 ng/ml) for 120h. PBMC were then pulsed with media alone plus DMSO (Unstim) or 1μg/pep/mL of 10 overlapping 18-mers spanning HCV NS3 1073 (HCV NS3 Pep), or anti-CD3/anti-CD28 (CD3/CD28). Intracellular IFN-γ was measured by intracellular cytokine staining. A) Representative flow cytometry plots of HCV-specific IFN-γ produced by T cells cultured in media alone or with recombinant human IL-21. Summary of flow cytometry data showing IFN-γ secreted by B) HCV peptide pulsed and C) CD3/CD28 stimulated CD8⁺ T cells. IFN-γ induction displayed as percentage of IFN-γ production from CD8⁺ T cells minus no peptide background (Unstim). Statistical significance was calculated using 2-tailed paired T-test. P< 0.05 considered statistically significant.