Fig. 1

Induction of IL-32 is involved in cytokine-mediated inhibition of HBV. a Huh7 cells were treated with the indicated concentrations of TNF-α and IFN-γ for 48 h, and the IL-32 level was determined by western blot analysis. Relative cell viability was measured by the XTT method. b Expression of IL-32γ induced by cytokines or transient transfection was observed by immunofluorescence assay. Magnification, ×400; scale bar, 50 μm. c Huh7 cells were transfected with the HBV 1.2 and GFP plasmids and treated with TNF-α and IFN-γ. HBV replication was determined by Southern blotting. Expression levels of IL-32 and GFP (transfection control) were determined by western blotting. d HBV 1.2 and siRNAs (20 nM) were co-transfected into Huh7 or HepG2 cells. Next day, cytokines were added with fresh medium. HBV replication and IL-32 expression were determined by Southern and western blotting, respectively. p < 0.05 by Student’s t-test. e Huh7 or HepG2 cells were transfected with the HBV 1.2 plasmid and treated with recombinant human IL-32γ (rhIL-32γ) for 3 days. HBV replication was determined by Southern blotting. f The levels of the IL-32 protein in culture medium and lysates of cytokine-treated Huh7 cells were determined by ELISA. The total amount of secreted (supernatant) or intracellular IL-32 in whole cells grown in a 12-well plate are shown. g The levels of the IL-32 protein in culture medium and lysates of cytokine-treated PHHs and differentiated HepaRG cells were determined by ELISA. Dashed bars represent the level of IL-32 obtained after transfection with pCAGGS (control) or IL-32 plasmids. Data (a, c, d, f, g) were obtained from three independent experiments (mean ± S.D.). p < 0.05 by Student’s t-test