Development of a safe and effective nanoparticle-based vaccine against porcine epidemic diarrhea virus 2308286

Abstract Introduction Porcine epidemic diarrhea virus (PEDV), introduced into the U.S. in 2013, causes severe diarrhea and nearly 100% mortality in neonatal piglets, leading to an estimated annual economic loss near $1.8 billion. Current inactivated vaccines provide only partial protection, while live-attenuated vaccines pose safety concerns. To address this, we are developing a hybrid nanoparticle (hNP)-based spike protein vaccine with enhanced safety, immunogenicity, and protective efficacy. Methods The nanovaccine incorporates the C-terminal domain (CTD) of the PEDV USA/CO/2013/29619 spike protein. CTD is expressed in E. coli, purified, and conjugated to lipid-coated poly(lactic-co-glycolic acid) nanoparticles. The hNP platform enables incorporation of molecular adjuvants within both the polymer core and lipid layer. Nanoparticles are characterized for size, polydispersity, antigen loading, and endotoxin levels. The immunogenicity of the nanovaccines is first evaluated in mice. Results Recombinant CTD was expressed at a yield of 30 mg/L in bacterial culture and purified under denaturing conditions with subsequent refolding. Endotoxin was reduced to below 1.0 EU/mL. hNPs exhibited a size under 200 nm with a polydispersity index below 0.1, reflecting high formulation uniformity. CTD was conjugated efficiently at 35 µg/mg of hNPs. Multiple formulations have been produced with various adjuvants, including CpG oligodeoxynucleotide, resiquimod, and monophosphoryl lipid A. The nanovaccines are evaluated in eliciting systemic IgG, mucosal IgA, and cellular immune responses relevant to PEDV protection. Conclusion This modular hNP platform allows precise antigen display and flexible multi-adjuvant delivery. This platform represents a valuable approach for advancing PEDV vaccine development and improving swine health outcomes. Funding Source USDA National Institute of Food and Agriculture, AFRI project 2021-08581. Topic Categories Vaccines and Immunotherapy (VAC)