Multivalent display of VP28 on chimeric virus-like particles enhances binding to shrimp target tissues: A novel antiviral strategy against white spot syndrome virus.

BACKGROUND AND AIM: White spot syndrome virus (WSSV) is a devastating pathogen in shrimp aquaculture, with viral protein 28 (VP28) playing a critical role in host cell attachment and entry. The extracellular domain of VP28 (residues 35-95) is immunogenic and essential for infection; however, its receptor interaction mechanisms remain incompletely elucidated. This study aimed to evaluate the tissue-binding affinity of full-length VP28 and its derived peptides (P1: Residues 35-65; P2: Residues 66-95) as well as a multimeric chimeric virus-like particle (K5-VLP) displaying VP28 on the surface of Macrobrachium rosenbergii nodavirus capsids to enhance host tissue interaction.

MATERIALS AND METHODS: Recombinant VP28, synthetic peptides (P1, P2), and chimeric K5-VLP were produced and characterized. Binding and inhibition assays were performed using enzyme-linked immunosorbent assay and immunofluorescence microscopy on shrimp gill, hemocyte, muscle, stomach, and hepatopancreas tissues.

RESULTS: Full-length VP28 exhibited strong binding to gill, hemocyte, and muscle tissues. The P1 and P2 peptides showed moderate binding compared to rVP28. Notably, K5-VLP demonstrated a 1.7-fold higher binding affinity than rVP28 in gill tissues and significantly outperformed P1 and P2 peptides. Inhibition assays confirmed that K5-VLP more effectively interfered with VP28 binding than peptides. Structural analysis and transmission electron microscopy confirmed correct assembly and surface presentation of VP28 on the VLPs.

CONCLUSION: Multimeric display of VP28 on K5-VLP enhances its binding affinity to shrimp tissues compared to monomeric or peptide forms. This suggests a promising platform for antiviral strategies, including competitive inhibition of WSSV entry and targeted therapeutic delivery in shrimp aquaculture.