IRFs are core transcription factors of IFN-λ genes. IL-28B (B), or IL-29 (C) in combination with siRNA specific for IRF-3, IRF-7, RELA(NF-κB p65), or control. At 36 h post-transfection, cells were stimulated with poly(I:C) for 6 hours or infected with JFH-1 for 12 h. Luciferase activity in whole cell lysates was normalized to Renilla luciferase activity. Data represent mean ± SD of triplicate data points of one experiment and are representative of three independent experiments. Statistical significance (p<0.01) is relative to control + poly(I:C) or control + JFH-1.