Costimulatory molecule programmed death-1 in the cytotoxic response during chronic hepatitis C

Figure 6 PD-1 up-regulation induced by HCV-core protein. A: FACS^® dot-plots and histograms of peripheral blood CD8⁺ cells stained with PD-1-FITC and CD8-Cy mAbs from a healthy subject. CD8⁺ cells were stimulated with B-galactosidase, HCV-core protein, CD3-CD28 mAb, and HCV-core protein plus CD3-CD28 mAbs. PD-1 expression was highly up-regulated on CD8⁺ cells after non-specific stimulation by anti CD3/CD28 mAbs in the presence of HCV core protein; B: FACS^® dot-plots and histograms of peripheral blood CD8⁺ cells stained with Ki-67 FTIC and CD8-Cy mAbs from the same healthy subject to test proliferation ability of CD8⁺ cells after incubation with B-galactosidase, CD3-CD28 mAb, HCV-core protein plus CD3-CD28 mAb and HCV-core protein plus CD3-CD28 and anti-PD-L1 mAbs. HCV-core protein decreased the proliferation induced by CD3-CD28 mAb stimulation. This proliferation impairment induced by HCV-core protein was resolved by anti-PD-L1 mAb treatment.