Additionally, the protein concentrations of IFN-γ, IFN-λ1, IFN-λ3, and IFN-λ4 in the infected cell culture supernatants were significantly enhanced by PRRSV at 12–48 h postinfection, displaying rapid decline with the duration of virus infection (Figures 3A–D). Here, IFNL4 is linked to viral infectious disease.