IRF7 and viral infectious disease: Compared to fish infected with GCRV-II alone, qPCR and western blotting showed that the SA-pretreated groups had much lower expression of key immune genes, such as IRF3, IRF7, IFN1, and IFN3 (Fig 7G-7K), indicating that SA treatment not only decreased viral infection but also mitigated the immune overactivation triggered by the virus.