To further verify that influenza virus induces SOCS-3 via an RNA sensory pathway and in an NF-kB dependent manner we infected cells with the influenza A virus mutant deficient for NS1 (DNS1) (Figure 6G and 6H) . The NS1 protein is known to block RNA dependent signaling and NFkB activation [55] . Accordingly, infection of cells with the mutant virus resulted in a more pronounced and sustained, albeit delayed induction of SOCS-3 ( Figure 6G ) if compared to infection with the isogenic wild type, that is a very poor inducer of SOCS-3 but still reasonably well induces IFNb. Noteworthy, this isogenic wild type strain differs from the PR8 wild type virus used in the other experiments shown here (see Materials and Methods for details).