FIG. 3.

Cell surface expression of HCV glycoprotein E2. Naive (B and D) or infected (A and C) Huh-7 cells grown on coverslips were labeled with the anti-E2 MAb 3/11. A set of cells was fixed with 3% paraformaldehyde and processed for immunofluorescence labeling after permeabilization with Triton X-100 (A and B). Cell surface labeling (C, D, E, and F) was carried out on ice with MAb 3/11 before the fixation with 3% paraformaldehyde and the incubation with Alexa488-labeled secondary antibody. Huh-7 cells transfected with a plasmid expressing wild-type HCV envelope glycoproteins (phCMV-E1E2; panel E) or HCV envelope glycoproteins containing a mutation of the charged residues in the transmembrane domain of E2 [phCMV-E1E2(LAL); panel F] were used as controls of cell surface expression of E2. All images were acquired and processed with the same settings. Bar, 50 μm.