TABLE 2.

Comparison of RSV detection by viral culture and real-time PCR in RSV-infected epithelial cells

Yield or expression level	MOI ata:
	0.001	0.01	0.1
Viral yield (log10 PFU/ml)	2.24 ± 0.06	3.26 ± 0.20	4.77 ± 0.25
RSV gene expression levelb	0.004 ± 0.001	0.069 ± 0.005	1 ± 0.1909
RSV genome levelc	0.0009 ± 0.0002	0.020 ± 0.003	1 ± 0.117
RSV antigenome levelc	0.0003 ± 0.0002	0.005 ± 0.002	0.269 ± 0.057

^aA549 alveolar epithelial cells were infected with RSV at an MOI of 0.001 to 0.1. Forty-eight hours after infection, cell supernatants were collected for the quantification of viral yield by plaque assay, while cells themselves were lysed and used as a source of RNA for real-time PCR analysis of RSV transcripts.

^bThe expression of RSV NS1 amplicon was analyzed by real-time PCR, normalized by the expression of β-actin in the corresponding cell culture, and presented relative to the amount NS1 amplicon in infected culture with an MOI of 0.1 (assigned a relative value of 1).

^cExpression of RSV genome and antigenome was analyzed by real-time PCR, normalized by the level of β-actin in the corresponding cell culture, and presented relative to the amount genome in infected culture with an MOI of 0.1 (assigned a relative value of 1).