Virus. The NS1 protein of type A influenza viruses suppresses innate immune system signaling activated by the PAMPs, via TLR3, TLR4, RIG-I, and MDA5 system. The suppression should contribute to efficient replication of infected virus in respiratory epithelial. The mechanism of suppression is mainly via inhibition of IRF-3 phosphorylation [43] , leading to suppressed induction of IFN-α/β, and IFN-λ1, 2, and 3. In addition, inhibition of NF-κB and AP-1 activation in influenza virus infected cells leads to suppressed proinflammatory cytokine production, for example, IL-8 and TNF-α. Influenza virus NS1 protein is known to be a multifunctional protein able to inhibit the type I IFN induction, the IFN-induced antiviral activity, the binding and sequestration of dsRNA, the interference with the host mRNA processing, the facilitation of preferential viral mRNA translation, and the inhibition of DC activation [44, 45] .