MAPK3 and viral infectious disease: After 4 h of viral infection (Figure 5A), the expressions of P65, p-P65 as well as p-P65/P65 were significantly reduced in the PRV-infected cells compared to uninfected control; the expressions of ERK1/2, p-ERK1/2, P38, and p-P38 as well as p-ERK1/2/ERK1/2 and p-P38/P38 were elevated when compared with uninfected control.