(A) Immunoblot analysis of TBK1 and IRF3 phosphorylation in scrambled (Scr) shRNA- and DHX29 shRNA-transfected 293T cells stimulated with intracellular (IC) HMW Poly(I:C), IC LMW Poly(I:C), or Poly(dA:dT). (B) ISRE- and IFN-β-luciferase (Luc) activities in Scr shRNA- and DHX29 shRNA-transfected 293T cells stimulated with IC HMW Poly(I:C). ISRE-Luc activity was also determined in 293T cells cotransfected with HA-DHX29 (200 ng) and Scr shRNA or DHX29 shRNA. IFN-β-Luc and ISRE-Luc activities were normalized to the Renilla luciferase internal control and presented as the fold increase relative to unstimulated control cells. (C) Real-time PCR analysis of IFNB mRNA expression in Scr shRNA- and DHX29 shRNA-transfected 293T cells stimulated with IC HMW Poly(I:C), IC LMW Poly(I:C), or Poly(dA:dT). (D-F) PBMCs (D) and THP-1 (E) and RAW264.7 (F) cells were transfected with Scr siRNA or DHX29 siRNA and stimulated with LMW Poly(I:C), HMW Poly(I:C) or Poly(dA:dT) in lyo/vec form (Vec). IFNB, IFIT1, and IFIT2 mRNA expression levels and IFN-β production were determined using real-time PCR analysis and ELISA, respectively. Data from (B-F) are representative of three independent experiments and plotted as the mean ± s.d. *P < 0.05, **P <0.01, ***P <0.001 vs. the corresponding control.