Author: Verena Beck and Martin Walpot, acib GmbH
A purification process for vaccines produced via a measles vector platform will soon lead to a more flexible, reproductive and economic process contributing to the faster development and production of vaccines.
The importance of the fast development, production and release of new vaccines against infectious diseases could be seen during the Covid-19 pandemic. In order to facilitate such immediate reaction to new viruses, so-called platform processes are required for the production of vaccines. Platform processes can be easily and quickly adapted to different new targets with minimal changes of the process resulting in more economic process development. This also saves time and resources compared to processes that need to be developed from scratch for each new vaccine.
The measles virus platform
One of such platform processes for the production of vaccines relies on the measles virus. The measles virus vaccination using live attenuated virus has proven to be extraordinarily safe and highly effective after many years of use with minimal adverse effects and a long-lasting protection. By genetic modification, it is possible to insert additional genes into the attenuated measles virus so that it can display vaccine antigens against a new emerging virus on its surface. With one single technology vaccines for different viruses can be produced and in contrast to a conventional strategy there is no need to produce pathogenic virus for a so-called inactivated vaccine or attenuated viral vaccine in which the pathogenicity is weakened by cultivation in the laboratory. The technology to display other viral proteins on measles virus is faster and avoids the production of pathogenic viruses.
An important part of the vaccine production is the purification of the virus in order to remove impurities that remain from the production process and would cause adverse effects if present in the final vaccine product. It is a challenge to maintain the desired properties of the virus such as immunogenicity but to get rid of the impurities at the same time. An additional challenge, especially for the measles virus, is that the production process must take place in a closed system under aseptic conditions. Normally, the vaccine is sterile filtered at the end of the process, which is not possible for the measles virus due to its relatively large size.
New purification process
A new, highly flexible and reproducible purification process for a vaccine via the measles virus platform was introduced shortly: The process can be used in small laboratory scale for research purposes as well as in a larger scale to produce vaccines for clinical trials and even the market. The novel process consists of a flowthrough chromatography step in which the small impurities are retained in a solid matrix while the large virus remains in the process stream. This chromatography step can be easily adapted for different kinds of measles virus vectors with little effort. In contrast to conventional process regimes, in the novel process the ultrafiltration of the measles virus is done after the chromatography step resulting in reduced process time and higher product yields and purity. All process steps can be conducted in a closed system under aseptic conditions and can also be integrated into a continuous process, enabling production of a variety of vaccines in much faster time.
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