Duck Tembusu Virus (DTMUV) is a newly emerging avian flavivirus that causes substantial economic losses to the duck industry in Asia by causing severe egg drop syndrome and fatal
encephalitis in domestic ducks. During viral replication, host cells recognize the
RNA structures produced by DTMUV, which triggers the production of
interferons (IFNs) to inhibit viral replication. However, the function of duck type I and
type III IFNs in inhibiting DTMUV
infection remains largely unknown. In this study, we expressed and purified recombinant duck IFN-β (duIFN-β) and IFN-λ (duIFN-λ) in Escherichia coli and evaluated their
antiviral activity against
vesicular stomatitis virus (VSV). Furthermore, we found that both duIFN-β and duIFN-λ activated the ISRE promoter and induced the expression of ZAP, OAS, and RNaseL in duck embryo fibroblasts (DEFs). Notably, duIFN-β showed faster and more potent induction of ISGs in vitro and in vivo compared to duIFN-λ. Moreover, both duIFN-β and duIFN-λ showed high potential to inhibit DTMUV
infection in DEFs, with duIFN-β demonstrating better
antiviral efficacy than duIFN-λ against DTMUV in ducks. In conclusion, our results revealed that both duIFN-β and duIFN-λ can induce ISGs production and exhibit significant
antiviral activity against DTMUV in vitro and in vivo, providing new insights for the development of
antiviral therapeutic strategies in ducks.