Sriram et al. showed that in vitro stimulation of murine bone marrow-derived conventional dendritic cells (cDCs) by TLR7/9 ligands in presence of IL-4, mediates suppression of antiviral responses (IFNβ and IFN-responsive genes), resulting in increased permissiveness of cDCs to viral infection (42). Here, IL4 is linked to viral infectious disease.