Manufacturing of BoVLP-BVD vaccine combines a high innovative concept based on empty viral capsids (VLPs or “virus-Like-Particles”), not containing DNA, which is covered by antigenic determinants of BVD virus. This structure is manufactured by an expression platform (Pichia pastoris). After previous testing of the most reactive particles by in vitro tests against positive sera of BVD vaccinated animals, candidates have been produced at 1L scale. One of them was also tested in a 30 L fermentation as first approach to an industrial scaling of the process.
These vaccine prototypes have been used in: first trial in calves tested enhancement of an in vivo immune-response, which gave very promising results in terms of safety, DIVA confirmation and detection of antibody against BVD; first experiment in a model species (rabbit to determine differences between reactivity of the prototypes) required for prototype selection and composition of a solid patent application.
Further in vivo trials were performed: second experiment in rabbits showed the safety of different vaccine formulations including purified and non-purified extracts and the last experiment in this species tested a maximal concentration of the active substance in a dose-response trial based on the final vaccine formulation. Furthermore, a new experiment in calves testing humoral response and neutralizing antibody activity was performed. Regarding ex vivo trials, all combinations between potential adjuvants and active substance were tested in cytotoxicity and immune response assays in order to facilitate the determination of a final formulation.
Besides, different analytical methods were optimized. In this way, commercial ELISA tests have been adapted, implemented and validated, as well as in house developed tests to determine the reactivity against the antigenic determinants of the VLP-BVD.
Advice to focus the project development on an adequate regulatory frame was applied by means of an Innovation Task Force (ITF) meeting by the EMA, giving us a preliminary overview of the registration process to be followed.
A Target Product Profile has been stablished since safety and efficacy data were achieved through in vivo and ex vivo trials performance. IP was managed by the application for an EU Patent (nº EP21382933.6) which protects the selected peptide sequences used for the vaccine formulations from BVD-E2 protein. Lastly, dissemination and communication activities to share technical results of the project were addressed to professionals and general public. It is worthy to mention that, due to the COVID global situation, online events such as webinars or social networks updating have been prioritized.
