Inhibitory receptor expression is linked to recognition of viral antigen.

(A) CD127 expression of HCV-specific CD8+ T cells grouped depending on the autologous virus sequence. Cross-recognition was defined as sequence variation from consensus that has been previously shown to be cross-recognized [39]. (B) PBMC of patients with variant autologous sequences (see table 2) were stimulated for IFN-γ expression after short term culture with different concentrations of consensus peptide (black line) or variant autologous peptide (dashed line). Representative diagrams are shown for pts. 4, 24–27 and 32. Frequency of IFN-γ expression is shown on the y axis, peptide concentration (µM) on the x axis. Viral escape is indicated by the strongly reduced IFN-γ production after stimulation with the autologous peptide sequence. (C) Divergent CD127 expression by HCV-specific CD8+ T cells on two epitopes from a single individual (pt. 4) targeting the NS3-1406 and NS5-2594 epitopes. (D) Overlay histograms of PD-1, 2B4, CD160 and KLRG1 expression on NS3-1406-specific CD8+ T cells (CD127hi) and NS5-2594-specific CD8+ T cells (CD127lo) from patient 4.