IL-6 decreases the levels of HBV transcripts, core protein, and genome-containing nucleocapsids. Confluent cells (day0) were treated with or without 20 ng/ml of IL-6 for 2 days (day2), 4 days (day4) or 6 days (day6). For RNA analysis (panel for RNA), total RNAs were extracted and equal amounts of samples were subjected to Northern blot analysis to reveal the expression profile of the HBV transcripts, namely those of 3.5-kb and 2.4-kb/2.1-kb respectively. The expression level of 18S rRNA was used as an internal control for sample loading. For Western blot analysis (panel for Proteins), cell lysates were harvested and equal amounts of samples were separated by SDS-polyacrylamide gel electrophoresis. The total core protein was subsequently detected by immunoblot analysis with antibodies against core protein. The expression level of β-actin was used as an internal control for sample loading. For particle blot analysis, equal amounts of cell lysates were assayed for viral capsid by native agarose gel electrophoresis. HBV genome-containing nucleocapsids were then detected by Southern blot analysis of the disrupted nucleocapsids using an HBV-specific probe (panel for Genome-containing nucleocapsids). The signals including 3.5-kb RNA, core proteins and genome-containing nucleocapsids were quantified by densitometry analysis and expressed as the average percentage of respective control cells from three independent experiments to indicate the inhibitory effect of IL-6. Results shown are representative of three independent experiments. *: The reduction in levels of HBV genome-containing nucleocapsids was compared with that of core proteins and found to be highly significant (P < 0.05 as monitored by Pearson χ2 test).