Rethinking process development for influenza vaccine production
The propagation of influenza viruses in embryonated chicken eggs has been a common practice for vaccine manufacturing since the 1940's. In recent years, researchers from industry and academia have moved away from this traditional method towards cell culture-based production systems.
Our group contributes with a fully integrated influenza A virus (IAV) production process using suspension MDCK cells that are cultivated in chemically defined media. This process established could produce 300 vaccine doses per liter within 4–5 days and thus compete with egg-based and other cell-based production systems (Bissinger et al., 2021; Wu et al., 2021).
Nevertheless, the full potential of MDCK cells may not be exploited yet, and we thus move further by rethinking process development and by implementing state-of-the-art technologies. A single-cell cloning approach is applied to challenge current host cell options and to investigate whether monoclonal suspension MDCK cells can compete with the heterogonous cell cultures traditionally used in large-scale manufacturing. Clonal selection can result into a high number of candidate cell lines requiring detailed evaluation of growth performance and virus production capacities. We supported this evaluation by using a modern single-use microbioreactor system (ambr®15) with an initial screening, followed by process optimization using a design of experiments (DoE) approach at 10–15 mL scale. This is feasible as this system allows for 24 parallel cultivations performed under tight process control, which results in fast, reliable outcomes under minimal medium use. After top clone selection, process development is finalized by scaling into disposable benchtop stirred tank bioreactors at a 2 L scale for validation (Zinnecker at al., 2023).
Zinnecker et al. In preparation (2023)