The prevention of repression of DDX21 at the protein and mRNA levels occurred dose dependently in the PCV3-infected PK-15 cells (Figure 1E,F; p < 0.05) or in the 3D4/21 cells (Figure 1G,H; p < 0.05) at a multiplicity of infection (MOI) of 0.2, 1.0, and 5.0. This evidence concerns the gene DDX21 and infection.