Effect of RSV604 on viral RNA synthesis (A), virus release (B), and infectivity (C) in BHK-21 cells. BHK-21 cells were infected with RSV A2 at an MOI of 0.1 in the presence of DMSO (control), RSV604 (1× EC90, as in RSV ELISA in HeLa cells) or AZ-27 (1× EC90, as in RSV ELISA in BHK-21 cells). (A) The quantity of RSV RNA in the infected cells was determined by qRT-PCR at the indicated time points. (B) The amount of released virus was determined by qRT-PCR quantitation of the RSV RNA in the culture medium supernatants. (C) The infectivity of the virus released into the culture supernatants was determined by TCID50 assay. The data shown are means and SD (n = 2).