Discrimination of 2-fold variations in virus input.

<p>Virus replication was assessed in the presence of TPCK-trypsin (1 µg/mL). A 2-fold dilution series of the virus was prepared (32,000 to 250 TCID₅₀ per 100 µL per well). After incubation for 1 h at 37°C, a suspension of MDCK-London cells (30,000 in 100 µL) was added. At 6 h post-infection, experimental samples were prepared using SPR and subjected to qRT-PCR. For each virus strain, the RNA copy numbers were normalized to the mean value observed from cells infected with 250 TCID₅₀. Each point represents the mean ± SEM (n = 3).