MX1 and infection: Upon infection with H5N1-RL or a Renilla-expressing reporter virus based on the MxA-sensitive IAV strain A/seal/Massachusetts/1/198010,11 (H7N7-RL), high reporter activity was observed in A549-wt and A549-shMxA cells but replication was considerably reduced in A549-MxA cells due to the presence of MxA (Supplementary Figure S5a).