As shown in Fig 1A, while both infection with Sendai virus (SeV), a model RNA virus that preferentially stimulation RIG-I signaling [24,25], and LPS stimulation induced a robust response in the increase of IFN-β, ISG15 and ISG54 mRNA in both wild-type (WT) and ADAP knock-out (Adap-/-) macrophages, the induced expression levels of these genes were significantly lower in Adap-/- macrophages compared to that in WT macrophages, indicating ADAP is required for IFN-I response of macrophages to RNA virus infection or LPS stimulation. Here, ISG15 is linked to infection.