In absence of IFN signaling, there was no significant induction of RIG-I in both rhMPV-WT- and ΔG-infected cells at early time points of infection, although there was still a slight increase in RIG-I levels at 15 h p.i. in ΔG-infected cells (Fig. 3A), which was no longer observed at 24 h p.i. (data not shown). This evidence concerns the gene IFNA1 and infection.