| Muscovy duck reovirus (MDRV) is a pathogenic virus in waterfowl. The clinical symptoms mainly appear in the liver and spleen with gray or yellow-white necrotic points and it causes significant economic loss in the poultry industry in China.Since the host innate immunity plays a key role in defending against virus invasion, more and more attentions have been paid to the immune response triggered by viral infection. Innate immune response provides the first line of defense against invading viruses. The effective activation of innate immune response can directly inhibit virus infection and promote the development of the acquired-immune response. Therefore, study of the mechanisms underlying the regulation of innate immune response is of great importance.Here we found that the genomic RNA of MDRV was able to rapidly induce the production of interferons (IFNs) in host. Mechanistically, we used RNA interference technology to prove that MDRV infection induced robust expression of IFNs in host mainly through RIG-I, MDA5 and TLR3-dependent signaling pathways. In addition, we observed that silencing Visa expression in 293T cells could significantly inhibit the secretion of IFNs. Remarkably, the production of IFNs was reduced by inhibiting the activation of NF-kB or knocking down the expression of IRF-7. Furthermore, our study showed that treatment of host cells with IFN-β and IL-28A markedly impaired MDRV replication, suggesting that these IFNs play an important role in antiviral response during the MDRV infection.Importantly, we also detected the induced expression of RIG-I, MDA5, TLR3 and type I IFN in Muscovy ducks infected with MDRV at different time points. The results from in vivo studies were consistent with those in 293T cells infected with MDRV. Taken together, our findings reveal that the host can resist MDRV invasion by activating innate immune response involving RIG-I, MDA5 and TLR3-dependent signaling pathways that govern IFN production. |
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