BDNF-AS and infection: To determine the cytopathic consequence of infection on PBECs, duplicate wells from the same donor were infected with RSV A2, BT2a, BT3a, BT4a (n = 5 donors) (MOI = 0.1 or 5) or mock-infected (n = 2 donors) and monitored every 24 h thereafter by phase contrast microscopy.