RAB4A and infection: To assess the effect of the Rab family on RSV replication, we depleted Rab1a, Rab2a, Rab4a, Rab5a, Rab6a, Rab7a, Rab8a, Rab9a, and Rab11a by treating A549 cells with specific siRNAs (or control siRNA) for 24 h, followed by infection with purified RSV A2 and incubation for another 36 h.