Both WAVE bioreactors and N-1 perfusion bioreactors have been widely applied as separate steps in seed train expansion for mammalian cell culture. Although N-1 perfusion bioreactor is an effective tool for high seed density process, there are needs and interests to streamline the passaging scheme and replace this complicated and labor-intensive unit operation. Hence, an optimized, highly-efficient and simple seed train process is highly desirable to improve this platform. In this case, leveraging WAVE perfusion bioreactors at bench top scale (50L) for seed train expansion can reduce the number of required expansion steps and can potentially be used for direct inoculation of production bioreactors at the manufacturing scale. In this work, we first optimized the cell-specific perfusion rate and operation parameters for both the N-2 and N-1 WAVE perfusion bioreactors using one CHO cell line expressing a recombinant monoclonal antibody. The optimized perfusion rate schedule is able to maintain similar daily cell growth rate at high cell density and is successfully applied to three CHO cell lines, with similar cell culture performance. Exponential growth was observed throughout the seed expansion reaching &gt; 15 × 106 vc/mL and &gt; 80 × 106 vc/mL for the N-2 and N-1 perfusion bioreactors, respectively. This process was successfully scaled up from a 10-L WAVE perfusion bag to a 50-L WAVE perfusion scale. Cell cycle analysis also confirms that cell cycle phase profiles are comparable throughout the WAVE perfusion bioreactor step. Importantly, inoculation of cells from different stages of WAVE perfusion bioreactor demonstrated to have similar cell culture performance and product quality attributes, comparing to the platform N-1 perfusion bioreactor process. Using three different CHO cell lines, we showed that WAVE perfusion seed cultures can improve process efficiency by optimizing the number of seed expansion bioreactor steps with simplified operations.

Seed train intensification by implementing WAVE perfusion bioreactors

ACS Fall 2020 Virtual Meeting

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