Fig. 3

RIG-I and TLR3 upregulation by influenza virus infection was required for IFNβ induction and was suppressed in HBEC isolated from smokers. After infection of cells with IAV at an MOI of 1 for 24 h, total RNA was extracted and cell PRR mRNA expression was assessed by qRT-PCR. Transcript levels of RIG-I (a) and TLR3 (b) were normalized relative to the constitutively expressed β-actin gene. (c) HBEC from nonsmokers were first transfected with RIG-I or TLR3 siRNA for two days before IAV infection. Statistical significance was determined by ANOVA. Data were expressed as the means ± SEM from three separate experiments from different donors. * denotes significant difference compared to data from the IAV infected cells from nonsmokers (NS + IAV), P < 0.05