Development of a Cellular Membrane Nanovesicle-Based Vaccine Against Porcine Epidemic Diarrhea Virus

Highlights What are the main findings? A highly efficient veterinary vaccine platform was developed using cellular membrane nanovesicles (CMN) and validated for PEDV by presenting the spike protein. The CMN-based PEDV vaccine elicited robust humoral and CD8 + T cell immune responses in both murine and porcine models, accompanied by notable virus-neutralizing antibody production. What are the implications of the main findings? The CMN-based platform enables multivalent PEDV vaccine design by co-expressing spike proteins from diverse viral variants to elicit broad-spectrum protection. The CMN-based approach provides a versatile strategy for the modular development of polyvalent and multivalent veterinary vaccines via co-expression of antigens from distinct virus. Porcine epidemic diarrhea virus ( PEDV ) has emerged as a major pathogen responsible for porcine diarrheal diseases, causing outbreaks of severe diarrhea and high mortality in neonatal piglets, thereby inflicting severe economic losses on the global swine industry. Current commercial PED vaccines, comprising conventional inactivated and live attenuated formulations, have exhibited progressively diminished efficacy in the face of emerging PEDV variants. The development of high-efficiency vaccine platforms is therefore critical for PED control. This study engineered a cellular membrane nanovesicle (CMN)-based vaccine, which differs from existing inactivated or subunit vaccines by presenting the PEDV spike (S) protein on the cell membranes to mimic the bilayer phospholipid structure of the viral envelope. The full-length S protein (FS, aa 19-1309) or a truncated S protein fragment (TS, aa 19-726) was expressed in Expi293F cells, followed by extraction of cell membranes to assemble antigen-displaying CMN vaccines. Compared with commercial live attenuated vaccine, administration of the CMN vaccine elicited high-titer neutralizing antibodies and elevated IFN-γ-producing CD8 + T cells in murine studies. Safety assessments revealed no adverse effects on body weight, hepatic/renal function indices, or histopathological parameters in vaccinated mice. Furthermore, immunization of piglets elicited notable humoral and CD8 + T cell immune responses. Collectively, the strategy of CMN-based vaccine described herein delivers a potential PEDV vaccine platform, thereby offering a novel avenue for next-generation veterinary vaccine development.