FIG. 7.

Relative infectivity of HDV particles bearing increasing ratio of C147S infectivity-deficient/wt AGL. Production of SL-HDV particles was achieved by transfection of 10⁶ Huh-7 cells with 1 μg of pSVLD3 plasmid for production of HDV RNP, 1 μg of p124 for expression of wt L-HBsAg, together with 1 μg of a mixture of HA-tagged wt S-HBsAg and C147S S-HBsAg expression vectors. Ratios of C147S/wt plasmids were 0/100, 10/90, 20/80, 30/70, 40/60, 50/50, 60/40, 70/30, 80/20, 90/10, and 100/0. (A) Particles from 0.5 ml of supernatant from transfected cells were analyzed for S- and L-HBsAg proteins by immunoblotting after PNGase F treatment. Quantification of HA-tagged (wtS-HA) and C147S S-HBsAg signals is indicated as percentages of total S-HBsAg proteins. (B) After normalization of the different preparations of HDV virions for HDV RNA, infectivity was evaluated in cultures of HepaRG cells by measuring the accumulation of HDV RNA in cells harvested at day 7 postinoculation. Quantification of intracellular HDV RNA signals by phosphorimager is indicated as percentages of the value for wt SL-HDV. Specific infectivity (y axis) is indicated as a function of the C147S/total S-HBsAg ratio in the viral envelope (x axis).