Although the induction of IFN-β by AIV was weaker than that after poly I:C stimulation (probably due to viral NS1-mediated inhibition of MDA5 signaling and induction of IFN-β activity) (11, 45), our results agree with those of a previous study showing that silencing of cMDA5 and cTLR3 in WT cells results in a significantly reduced induction of IFN-β activity after stimulation with poly I:C or infection of AIV (39). This evidence concerns the gene IFNB1 and infection.