Outbreaks of joint and visceral gout in goslings caused by goose astrovirus (GAstV) continue to affect the goose industry in China. Currently, there is a lack of vaccines and drugs to treat GAstV-associated diseases. Due to the wide spread of GAstV through fecal-oral, vertical, and cross-host transmissions, the need to develop effective antiviral agents is urgent. In this study, the spike domain of the capsid protein of GAstV XX strain was targeted for the development of potential peptide ligands that possessed antiviral effect on GAstV infection. Molecular docking was performed to select the peptides with potential binding to the capsid spike of GAstV. The binding was then validated using an enzyme-linked immunosorbent assay (ELISA). After screening based on immuoperoxidase monolayer assay (IPMA), immunofluorescence assay (IFA), and Western blot, peptide AP21 was demonstrated to inhibit GAstV infection in LMH cells in a dose-dependent manner. The expression of capsid spike reduced significantly in GAstV-infected cells upon pre-incubation of the virus with AP21. In addition, AP21 reduced viral infectivity by more than 10-fold as determined by the 50% tissue culture infectious dose (TCID₅₀) assay. Structural analysis showed that the binding sites of AP21 on capsid spike were located on the surface of the protein and these sites were not linear but discontinued. In summary, the identification of antiviral peptides based on virtual screening and experimental validation greatly facilitated the development of antiviral peptides, which is important for the prevention and control of GAstV-associated gout diseases.

To Cite This Article: Wang Y, Li W, Li P, Chen L and Jin Q 2025. Identification of antiviral peptide ligands targeting the capsid spike domain of goose astrovirus. Pak Vet J. http://dx.doi.org/10.29261/pakvetj/2025.247