FIGURE 5.

Biological activity of SS^Ext mIFNγ(SP)₁₀ in suppressing IAV replication. MDCK cells were left uninfected or pre-incubated with DMEM (Mock), 800 ng of protein extracts from N. benthamiana healthy leaves as the negative control (N), or three different concentrations (50, 200, 800 ng) of PC- IFNγ, or SS^Ext mIFNγ(SP)₁₀, for 12 h followed by infection with IAV at an M.O.I of 1.0. (A) Western blot analysis of viral protein expression levels. At 24 hpi, total cells were harvested and subjected to western blot analysis for the determination of expression of viral proteins NS1 and NP. The amount of actin was used as the internal loading control. (B) Quantification of protein levels of NS1 and NP by densitometry. The accumulation level of viral proteins in DMEM (Mock) treated cells was arbitrarily set as 100% and the relative protein accumulation levels in N, PC-IFNγ, and SS^Ext mIFNγ(SP)₁₀ relative to Mock was plotted. Statistical analysis was performed using one-way ANOVA with Tukey’s post hoc multiple comparison analysis. Mean expression ratio (%) and SD from three independent experiments with technical triplicates are presented. The P-value of < 0.001 was considered significantly different, as denoted by different letters.