Figure 2.

U-exo treatment reduces IFV replication and shows a synergistic antiviral effect with IFN-α on IFV infection. (A) A549 cells were infected with IFV A/H1N1, IFV A/H3N2 and IFV B/Yamagata at an MOI of 1. After viral attachment, cells were treated with control (Ctl), U-exo (Exo), IFN-α (10 ng/mL), or IFN-α combined with U-exo (IFN-α+Exo) for 48 h, after which viral gene expression levels were measured using RT-qPCR. Expression levels of the viral nucleoprotein (NP) for IFV A/H1N1 or H3N2 or matrix protein 1 (M1) for IFV B/Yamagata were quantified and normalized against GAPDH. Data are shown as the mean ± standard deviation (SD) of the means from three independent experiments. (B) Viral titers were measured using the TCID₅₀ assay and expressed as TCID₅₀/mL (means ± SD; n = 3). Statistical analysis: *p < 0.05; **p < 0.01; ***p < 0.001, versus Ctl-treated cells. ^#p < 0.05; ^##p < 0.01; ^###p < 0.001, versus IFN-α-treated cells. (C) A549 cells were infected with IFV A/H1N1, IFV A/H3N2 and IFV B/Yamagata at an MOI of 1. U-exo were exposed to 1 μg/mL RNase for 1 h and added to IFV-infected cells. Viral gene expression levels were measured (means ± SD; n = 3). Statistical analysis: *p < 0.05; **p < 0.01; versus Ctl-treated cells. ^#p < 0.05, versus U-exo (Exo)-treated cells.