Modular Surface Engineering of Feline Parvovirus Virus-Like Particles for Antigen Presentation and Receptor-Mediated Cell Targeting

Virus-like particles (VLPs) are non-infectious, multiprotein nanostructures that mimic the architecture of viruses while lacking genetic material. Their structural versatility and safety profile make them promising platforms for biomedical applications, including vaccine development, targeted drug delivery, and diagnostics. Among various functionalization strategies, click-chemistry has emerged as a precise and efficient method for attaching bioactive molecules to VLP surfaces. In this study, we report the production and functionalization of VLPs derived from the feline panleukopenia virus (FPV), a parvovirus closely related to the well-characterized canine parvovirus (CPV). We demonstrate successful expression, assembly, and purification of FPV VLPs, followed by their modification with fluorophores, peptides, oligonucleotides, and proteins using copper-free click-chemistry. Furthermore, using cryo-EM, we structurally characterize FPV VLP functionalized with antigenic peptides, providing detailed insights for further development of such vaccine prototype. Finally, we demonstrate that our FPV VLP specifically transduce feline and human cells expressing transferrin receptor type 1 (TfR), thus validating their potential as a unique platform for future nanotechnological and therapeutic applications.