Role of TLR3 and RIG-I in PolyI:C-mediated IFN induction. (A) Effect of disruption of TLR3 function by Bafi A1 on the induction of IFN-β and IFN-λ by PolyI:C stimulation. hCMEC/D3 cells were pretreated with 100 nM Bafi A1 for 1 hour and then stimulated with 1 µg/mL PolyI:C for 16 hours. (B) hCMEC/D3 cells were stimulated with 1 µg/mL 5′ppp dsRNA or 5′ppp dsRNA control for 16 hours, washed with plain medium 3 times, and then cultured for 48 hours poststimulation. (C) hCMEC/D3 cells were pretransfected with RIG-I siRNA or control siRNA for 24 hours prior to stimulation with 1 µg/mL PolyI:C. RNA was extracted and IFN expression was measured by quantitative real-time polymerase chain reaction (qRT-PCR). Data were the mean ± SD of 3 independent experiments. Asterisks indicate that the differences between the indicated groups are statistically significant (*P < .05; **P < .01).