Development of a ferritin-based subunit nanoparticle vaccine targeting the S-RBD of porcine transmissible gastroenteritis virus.

Porcine transmissible gastroenteritis virus (TGEV) remains a critical economic threat to the global swine industry due to its near 100% mortality rate in newborn piglets within 5 days of age; however, current vaccine strategies, such as attenuated vaccines, are often limited by biosafety concerns, whereas traditional inactivated vaccines, while resolving biosafety issues, exhibit poor immunogenicity. To address these limitations, this study aimed to develop a novel subunit vaccine by engineering self-assembling ferritin nanoparticles engineered to display the TGEV Spike protein receptor-binding domain (S-RBD). By fusing the S-RBD to the N-terminus of ferritin via a flexible linker, we generated eukaryotic expression plasmids and produced the recombinant proteins at scale using a lentiviral-transduced ExpiCHO cell system. Subsequent characterization via SDS-PAGE, Western blotting, and transmission electron microscopy (TEM) revealed that both TGEV-S-RBD-FR and ferritin scaffolds were successfully expressed at their predicted molecular weights of 72 kDa and 40 kDa, respectively. Critically, TEM and particle size analysis confirmed that these constructs assembled into monodisperse, spherical nanoparticles, with a diameter increase from 15 nm to 25 nm, validating the successful external display of the S-RBD. Collectively, these results demonstrate the successful development of a nanoparticle platform, offering a promising and highly programmable strategy for the prevention and control of TGEV.