Mosaic Nanoparticles Based on Porcine Ferritin Induces Potent Protective Immunity in Pigs against Serotype O FMDV

The serotypes and subtypes of foot-and-mouth disease virus (FMDV) are highly diverse, making the research and development of cross-protective and high-efficiency foot-and-mouth disease (FMD) vaccines increasingly urgent. In this study, we designed and constructed two mosaic nanoparticles by fusing porcine Ferritin (pFt) and Lumazine Synthase (LS) protein as nano-scaffolds with B-cell epitopes (VP1 G-H loop) from multi-lineage strains of serotype O FMDV and a conserved 3D T-cell epitope using the prokaryotic expression system. The results of mouse experiments confirmed that compared with 3D-LS-mGHs (n = 8), 3D-pFt-mGHs (n = 8) can induce stronger specific protective immune responses in mice. Subsequently, the immune protective effect of the 3D-pFt-mGHs (n = 3) in pigs was evaluated. The results showed that immunization with 3D-pFt-mGHs could induce cross-neutralizing antibodies against against O/BY/CHA/2010, O/TZ/CHA/2010 and O/ES/CHA/2001 strains in pigs, elicit robust cellular immune responses, and confer protection against FMDV serotype O infection in pigs. Collectively, the developed 3D-pFt-mGHs mosaic nanoparticle vaccine possesses great application potential for cross-neutralizing and control of serotype O FMDV.