Construction and Immunogenicity Evaluation of Recombinant Adenovirus-Expressing Capsid Protein of Foot-and-Mouth Disease Virus Types O and A

The objective of this study was to construct a recombinant adenovirus expressing the foot-and-mouth disease virus (FMDV) capsid protein of types O and A for future FMDV vaccines to be used in the livestock industry for the reduction in losses caused by FMD outbreaks. Three recombinant adenoviruses, rAdv-P12A3B3C-OZK93, rAdv-P12A3B3C-OA58, and rAdv-P12A3C-AF72, were packaged, characterized, and amplified using the AdMaxTM adenovirus packaging system, and the humoral and cellular immunity levels were further evaluated in guinea pigs with monovalent or bivalent forms. The results showed that the three recombinant adenoviruses could elicit high levels of humoral and cellular immune responses against FMDV types O and A when immunizing monovalent or bivalent forms, and the immune effect changes with the change in the proportion of recombinant adenovirus types O and A, laying an important foundation for the future development of a new FMD live-carrier vaccine. These results implied that the recombinant adenovirus expressing the FMDV capsid protein of types O and A could be used to prevent FMDV in livestock.