FIG. 6.

Comparison of HBV envelope proteins produced in PTHs and Huh7 cells. Secreted particles from Ad-HBV1.3-transduced PTHs (lanes T; MOI, 125; 9 ml of medium from days 7 and 8) and Huh7 cells (lanes H; MOI, 400; 20 ml of medium from days 3 and 4) were separated on similar CsCl gradients as shown in Fig. 5, and the proteins from the HBsAg peak fractions were analyzed by Western blotting with monoclonal antibodies specific for S (4/7B), pre-S2 (S26), and pre-S1 (MA18/07); the αpre-S2 and αpre-S1 blots were obtained sequentially without intermediate stripping. Detection was performed using a chemiluminescent substrate. The positions of protein size markers (in kilodaltons) are indicated on the left, and the various forms of the S, M, and L proteins are given on the right. The arrow marks a doublet of bands in the T lane of the αS blot that superficially resemble L proteins but are probably nonspecific.