IFNB1 and infection: In hMPV-infected cells, STAT2 phosphorylation was detectable at 15 h p.i. In this condition, IFN-β treatment of hMPV-infected cells did not result in a further increase of STAT2 phosphorylation (lane 8 vs lane 7 and lane 6), suggesting that hMPV infection also affects IFN-β-induced STAT2 activation.