Mosquito defensin facilitates Japanese encephalitis virus infection by downregulating the C6/36 cell-surface antiviral protein HSC70B.

Japanese encephalitis virus (JEV) is a viral zoonosis that can cause viral encephalitis, death and disability whose primary vector is the Culex mosquito. Viral infection induces a series of antimicrobial peptide responses in mosquitoes, and the effector defensin enhances JEV replication in mosquitoes. However, the underlying mechanisms by which defensin enhances JEV are not fully understood. Here, we found that mosquito defensin could downregulate the antiviral protein HSC70B and enhance virus infection in mosquitoes. The cell-surface protein HSC70B was significantly downregulated by JEV infection and defensin treatment. Low levels of HSC70B were beneficial to JEV infection in mosquitoes. Taken together, these findings show that defensin and HSC70B axis facilitates JEV infection in the mosquito.