Optimization of Influenza Virus Purification

Presented by Raquel Fortuna

Raquel Fortuna is a PhD student at Max-Planck-Institute Magdeburg, Germany.

According to Business Wire, the worldwide market for influenza virus preparations is booming, estimated to grow from $6.1 billion in 2016 to $10.2 billion by 2022. Vaccines are projected to represent about 80% of the influenza market, with therapeutics filling in the remainder.

Influenza is a high-impact disease, causing three to five million severe cases with 250,000–500,000 attendant deaths throughout the world every year. Most at risk are the very young and the aged. Furthermore, the economic toll due to lost workforce productivity and the strain on public health services can be substantial, especially in underdeveloped nations that are already struggling with multiple disease challenges. Although a few antiviral drugs are available, their efficacy is limited, and an effective vaccine is by far the most efficient way to prevent infection. Unfortunately, the virus is constantly undergoing antigenic drift, meaning that a new vaccine must be produced every year.

Max-Planck-Institute Magdeburg, Germany

Raquel Fortuna is a PhD candidate and member of the Bioprocess Engineering Group headed by Prof. Dr.- Ing. Udo Reichl at the Max Planck Institute for Dynamics of Complex Technical Systems in Magdeburg, Germany. The downstream processing team has focused (among other topics) on pseudoaffinity membrane chromatography for viral purification. This system relies on the use of sulfated cellulose membrane absorbers (SCMA), which are thin, synthetic, macroporous membranes, derivatized with functional sulfate groups comparable with those on the equivalent resins. They are particularly useful in viral purification because they combine the advantages of high affinity with high-convection flow rates.

In the study presented, the overall goal was to find the optimal combination of the factors that would maximize yield and minimize loss and levels of contaminants. This was accomplished by implementing a design of experiments (DoE) approach, considering membrane-related factors (including ligand density and flux rate) and process-determined factors, including flow rate, elution salt concentration, feed conductivity, and feed concentration.

During the investigations, it was determined that, overall, operational conditions are more relevant than the membrane characteristics. In particular, low conductivity of the feed stream and high virus concentrations have the highest impact on the purification process. At the same time, the team found that the flow rate and salt concentration during elution had only a moderate influence on the performance. Finally, moderate to high ligand densities were beneficial, and flux was found not to be a relevant factor in this model.

Given these findings and their combination with the inherent advantages of using a membrane chromatographic support, SCMA can be considered a valuable platform technology for influenza virus purification.