2.7. RSV qRT-PCR assay

At the indicated time points p.i./compound incubation, total RNAs were extracted from supernatants, after freezing and thawing the infected cells, with QIAamp® Viral RNA Mini Kit (QIAGEN, USA) according to the manufacturer's instructions. The first-strand cDNA synthesis was performed with SuperScript III Reverse Transcriptase (SSIII) (Thermo Fisher Scientific) following manufacturer's instructions and a primer which recognizes the M gene of the negative-strand RSV RNA genome. Then a quantitative PCR (qPCR) with primers and probe targeting the M gene previously reported (^{Kim et al., 2011}) was performed with SensiFAST™ Probe No-ROX Kit (Bioline) following manufacturer's instructions. RNase P DNA was used as a reference gene and was amplified with the corresponding gene specific primers and probe and the qPCR was performed with SensiFAST™ Probe No-ROX Kit (Bioline). Average viral RNA Cq values were normalized to the average Cq values of RNase P and ΔΔCt based fold-change calculations were set relative to untreated-virus infected cells at 6 h p.i.