Increasing antibody yield and modulating final product quality using the FreedomTM CHO-STM production platform
© Sabourin et al; licensee BioMed Central Ltd. 2011
Published: 22 November 2011
Cell line development (CLD) is a critical step in the generation of biotherapeutics, but it is still hindered by several pain points, including the lengthy and labor-intensive workflow needed to isolate desirable clones, lack of reproducibility, as well as potential protein quality issues. Over the last decade, antibody titers in mammalian cell culture systems in excess of 3 g/L have been achieved through the use of novel media and feeds. However, it is still a challenge to consistently and rapidly create a stable cell line and a cell culture process capable of supporting both high antibody yield and acceptable post-translational modifications while managing the effort required for execution of the workflow. The goal of the study was to develop a robust and reproducible stable cell line workflow to generate scalable high-producing clones in less than 6 months, with industry-standard titers and desirable product quality using minimal effort.
Using CHO-S™ as the host cell line, we first evaluated if a single medium could be used for the entire CLD workflow, therefore avoiding the issues and complications of changing media during this process. We investigated if a formulation previously shown to increase titer as a production medium could in fact be used for all CLD steps, from transfection to stable pool isolation all the way through to clone productivity, without compromising titers or performance. The same rich production medium was used in limiting dilution cloning and compared to a lean cloning medium prototype. Furthermore, robustness of the workflow was verified by testing multiple molecules. We also explored reducing effort by streamlining all the steps of the workflow. Finally, we assessed top clone scalability and expressed product quality. We tested whether clones chosen only by titers responded well to scale-up and process development in a model bioreactor setting. In addition, product glycosylation from these clones was compared to the same molecule produced in CHO DG44 cells, a well-characterized production platform.
Molecule 1 clone productivity during scale-up from shake flask to bioreactor.
Molecule 1 clone
Shake flask simple fed-batch (g/L)
Shake flask fed-batch (g/L)
Bioreactor fed-batch (g/L)
The use of a single medium for the entire workflow is revolutionary, and has the distinct advantage of avoiding any need for media adaptation at any point in the workflow, whether it be preceding or following cloning, or for productivity assessment. This in turn avoids any undesirable genetic selection that may occur during such adaptation steps, and facilitates streamlining the workflow for ease of use and efficiency. Clones are easily scaled from shake flask to bioreactor and produce 2-3 g/L with minimal process development. Product glycosylation in top CHO-STM clones was comparable to historical data from CHO DG44-derived clones expressing the same molecule. In addition, the establishment of clone stability and acceptable glycosylation patterns are key attributes required for regulatory approval of biotherapeutic production. Together, these results demonstrate the capabilities of the FreedomTM CHO-STM Kit as an efficient and robust stable CLD platform, which can be accessed without the burden of milestone or royalty payments.
This article is published under license to BioMed Central Ltd. This is an open access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.