ISG15 and infection: Following RSV-L19 infection (MOI = 10) of sh-ARCN1-RAW264.7 cells for 12 h, RT-qPCR analysis revealed significantly increased mRNA levels of Ifnb1 and interferon-stimulated genes Isg15 and Ifit1 compared to sh-NC-RAW264.7 controls (Fig 3a), suggesting that ARCN1 suppresses RSV-induced IFN-β signaling.