Since rCsISG15 induced significant inductions of CsIL8, CsCCK1, CsCXCe1, IL-1β, and TLR9, which are involved in innate immunity against pathogen infection, it is likely that the anti-megalocytivirus effect of rCsISG15 is the result of augmented cellular immune response rather than a direct interaction between rCsISG15 and the viral pathogen. The gene discussed is TLR9; the disease is infection.