Figure 4
Indispensible role of type I interferon in RIG-I-dependent 5'PPP-RNA-induced antiviral effects. (A). A549 cells (1 × 106/well) in a 6-well plate were transfected with control siRNA or siRNA against RIG-I or IFN αβ receptors using DharmaFect 1 transfection reagent as per manufacturer instructions (Dharmacon, Lafayette, CO, USA). After 24 hr, cells were transfected with 2 μg of 5'PPP-RNA. A549 cells were then infected with A/New York/02/2001, a H1N1 virus at 0.1 MOI. Supernatants collected after 24 hr were analyzed for virus growth by plaque assay using MDCK cells. (B) A549 cells from experiment (A) were also analyzed for IFNβ and RIG-I expression by quantitative RT-PCR as described elsewhere. Data shown represent the mean ± SD of three independent experiments.