Figure 2.

Envelope and core protein levels. Huh7 cells were transfected with a plasmid encoding the untagged WT HBV S protein or S-His, or WT untagged L, L-His or core proteins. Three days after transfection, the cells were analyzed by western blotting for HBsAg secretion, and by confocal microscopy. (A) Cell lysates were separated by SDS-PAGE, the bands were transferred onto membranes and the membranes were probed with anti-HBs (left panel), anti-His (central panel) or anti-HBc (right panel) antibodies. The asterisk (*) notes the presence of a truncated version of the S and S-His proteins. (B) A commercial ELISA was used to quantify HBsAg in cell supernatants. The amount of S-His secreted was about half the amount of WT S secreted. The bars indicate the mean ± standard deviation (SD) values from four independent experiments. p values (paired t-tests) were determined: ***p value < 0.001. (C) Cells were fixed on coverslips and proteins were visualized by confocal microscopy after indirect immunofluorescence with an anti-HBs antibody (in green) together with an anti-His antibody (in red) for the L or S proteins, or with an anti-HBc antibody (in red) for the core protein. Nuclei were labeled with DAPI (in blue).