Feline Calicivirus P39 Inhibits Innate Immune Responses by Autophagic Degradation of Retinoic Acid Inducible Gene I

Feline calicivirus (FCV) is a feline pathogen that can cause severe upper respiratory tract disease in cats, thus posing a major threat to their health. The exact pathogenic mechanism of FCV is still unclear, although it has been identified as having the ability to induce immune depression. In this study, we discovered that FCV infection triggers autophagy and that its non-structural proteins, P30, P32, and P39, are responsible for initiating this process. Additionally, we observed that altering autophagy levels via chemical modulation resulted in different influences on FCV replication. Moreover, our findings indicate that autophagy can modify the innate immunity induced by FCV infection, with increased autophagy further suppressing FCV-induced RIG-I signal transduction. This research provides insights into the mechanism of FCV replication and has the potential to aid in the development of autophagy-targeted drugs to inhibit or prevent FCV infection.