Fig 5.

Invariant-chain degradation is inhibited by HCV infection or transfection with HCV core/NS5A. (A) Hepatocytes were infected with HCV genotype 1a or 2a. Cell lysates prepared 5 days after infection were analyzed for invariant-chain (CD74) expression by Western blotting. Mock-infected cells were treated as controls for comparison. (B) Huh7 cells transfected with HCV core or NS5A were analyzed similarly for expression of CD74 by Western blotting. (C) Cell surface expression of CD74 on HCV core- and NS5A-transfected Huh7 cells, stimulated or not with 500 U/ml IFN-γ for 48 h. The results of FACS analyses after immunostaining with anti-CD74 antibody, followed by FITC-conjugated goat anti-mouse treatment, are shown. (D) IHH were transfected with plasmids containing HBV X to enhance HLA-DR expression. The transfectants were stimulated with 500 U/ml IFN-γ, and CD74 cell surface expression was examined after 48 h by FACS. (E) Huh7 cells were treated or not with cathepsin S inhibitor (2.36 μM) and stimulated with 500 U/ml IFN-γ for 48 h. Cell surface expression of CD74 was examined by FACS. The result from cells stained with a secondary antibody is shown as the negative control.