Figure 3: TCF1⁺CD127⁺PD1⁺ HCV-specific CD8⁺ T cells are maintained after cessation of antigen stimulation.

CD127/PD1 subset distribution of HCV epitope-specific CD8⁺ T cells after cessation of antigen stimulation by direct acting antiviral (DAA) therapy (n=9–16). (a) Viral loads (HCV RNA) in the sera of DAA-treated HCV patients (n=20) were determined at the indicated time-points. Lower detection limit is indicated by dashed line. (b) Representative dot plots showing CD127/PD1 subset distribution of HCV epitope-specific CD8⁺ T cells (red) at baseline (left) and at the end of DAA therapy (EOT; right) (grey: corresponding bulk CD8⁺ T cells). (c–e) Statistical graphs depicting frequencies of the indicated CD127/PD1 subset among HCV epitope-specific CD8⁺ T cells during DAA-mediated cessation of antigen stimulation. (f,g) Frequencies of CD39⁺ and Eomes^hi HCV epitope-specific CD8⁺ T cells during DAA-mediated cessation of antigen stimulation. (h) Representative flow cytometric dot plots depict CD127/PD1 co-expression of TCF1⁺ HCV epitope-specific CD8⁺ T cells (green; grey: corresponding bulk HCV epitope-specific CD8⁺ T cells) at baseline (left) and at the end of DAA therapy (EOT, right). Frequencies of TCF1-expressing HCV epitope-specific CD8⁺ T cells (i) and TCF1-expressing CD127⁺PD1⁺ HCV epitope-specific CD8⁺ T cells (j) during DAA-mediated HCV elimination. Statistical significance was assessed by Friedman and Dunn’s multiple comparison tests. (*P<0.05; **P<0.01; ***P<0.001; ****P<0.0001.)