Figures 1E,F show that the level of IGF1 protein expression in the A549 cells following PR8 infection was consistent with the level of IGF1 mRNA; however, such upregulation times were lower than the level of mRNA. Compared with the Mock group, the level of IGF1 protein expression peaked 1.82 times at 48 h after PR8 infection at a MOI of 0.5 (Figure 1E). The level of IGF1 protein expression was also increased following the increasing of MOI. At a MOI of 1.0, the level of IGF1 protein expression reached 2.26 times that of the Mock group at 48 h post-infection (Figure 1F). This evidence concerns the gene IGF1 and infection.