Comparison of transcriptional profiles of interferons, CXCL10 and RIG-1 in influenza infected A549 cells stimulated with exogenous interferons.

Type I and type III interferons (IFNs) are induced by viral infection. It was concluded that these IFN species are identical in regulation and biological functions. However, these two systems differ in the tissue expression of their receptors and their transcriptional regulation is fundamentally different as well as cellular signaling pathways that drive expression of each IFN. Here, we have investigated the transcriptional profile of endogenous IFNs after stimulation of cells with exogenous IFNs and subsequent infection of A549 cells with A/chicken/Germany/27 [H7N7] influenza virus. Both type I and type III IFNs exhibit high degree of the cross-induction. Our results show that type III IFNs (IFN-λ1, IFN-λ2 and IFN-λ3) are better inducers of CXCL10 than type I IFNs. The IFN-β1a and IFN-λ2 were the most potent IFNs and they highly increased the level of IFN-α, IFN-β, IFN-λ, and CXCL10 mRNAs. Since type I IFNs up regulated expression of retinoic acid-inducible gene 1 (RIG-1) mRNA, type III IFNs-λ down regulated expression of RIG-1 mRNA in influenza infected cells. IFN-α and IFN-ω induced similar amount of IFN-α, IFN-β and IFN-λ mRNA but differ in induction of CXCL10 and RIG-1 mRNA.