Antimicrobial peptide WK-13-3D inhibits Japanese encephalitis virus infection by interacting with viral particles, potentially targeting the envelope protein.

Despite causing fatal encephalitis and long-term neurological, cognitive, and behavioral impairments in survivors, no antiviral drugs are currently available to treat Japanese encephalitis virus (JEV) infections, highlighting the urgent need for effective therapies. Antimicrobial peptides (AMPs) exhibit broad-spectrum antibiotic activity; LL-37 is one such AMP that demonstrates a broad antiviral effect against various viruses. However, some viruses resist LL-37 and its analogues, emphasizing the importance of studying the impact of specific antimicrobial peptides on different viruses. In this study, we found that the synthetic LL-37 analogue peptide WK-13-3D has strong antiviral activity against JEV. Notably, pre-treatment or co-incubation during virus adsorption led to a noticeable reduction in infection levels in human glioblastoma (T98G) cells. Mechanistically, WK-13-3D inhibits JEV infection by directly binding to the viral particle, potentially Envelope (E) protein and preventing internalization. This peptide conferred protection against mortality in JEV-infected mice. In vivo, pre-treating JEV with WK-13-3D provided complete protection against death, compared to only 16.66% survival in the control group. Overall, these results suggest that WK-13-3D could be a promising candidate for further development as an immediate post-exposure antiviral treatment or prophylactic intervention for JEV infection.