RNA viruses, such as foot-and-mouth disease virus (FMDV), have error-prone replication resulting in the continuous emergence of new viral strains capable of evading current vaccine coverage. Vaccine formulations must be regularly updated, which is both costly and technically challenging for many vaccine platforms. In this report, we describe a plasmid-based virus-like particle (VLP) production platform utilizing transiently transfected mammalian cell cultures that combines both the rapid response adaptability of nucleic-acid-based vaccines with the ability to produce intact capsid epitopes required for immunity. Formulated vaccines which employed this platform conferred complete protection from clinical foot-and-mouth disease in both swine and cattle. This novel platform can be quickly adapted to new viral strains and serotypes through targeted exchanges of only the FMDV capsid polypeptide nucleic acid sequences, from which processed structural capsid proteins are derived. This platform obviates the need for high biocontainment manufacturing facilities to produce inactivated whole-virus vaccines from infected mammalian cell cultures, which requires upstream expansion and downstream concentration of large quantities of live virulent viruses.

This report covers the methodology for generation of stable heterohybridoma clones producing Foot-and-mouth disease virus (FMDV) reactive porcine monoclonal antibodies (mAbs). Swine received five inoculations of an inactivated O1 Manisa FMDV vaccine prior to the harvest of splenocytes. Due to the lack of a species-specific hybridoma fusion partner, the Sp2/0 murine myeloma cell line was utilized for the formation of porcine-murine heterohybridoma clones. Twenty-nine FMDV-reactive parental clones were generated. Following sub-cloning and monitoring of reactivity over 20 serial passages, eleven subclones derived from unique parental origins were characterized and are reported herein. This methodology demonstrated the production of porcine mAbs by fusion of porcine splenocytes from immunized pigs with murine myeloma cells to generate heterohybridomas. The porcine immune response may differ from the murine immune response in relation to recognized epitopes. Therefore, application of this methodology may provide valuable resources for swine immunology and enhance the understanding of the mechanisms for antibody based protection from diseases in swine.