IFNA1 and infection: Furthermore, prior infection of BALB/c mice with hMPV completely suppressed IFN-α production induced by intranasal application of poly-ICLC (TLR3 ligand) or a synthetic CpG-ODN (TLR9 ligand) in mice lung [51], indicating that hMPV interferes with one or multiple signal transduction pathways activated in response to TLR stimulation in a variety of cell types.