A High Cell Density Approach to Fed-Batch Cell Culture for Production of Biopharmaceuticals

We have evaluated a more cell-intensive approach to both cell line adaptation and production culture as a means of achieving high integrated viable cell density (IVCD) in order to improve cell culture process yields. Shake flask based Fed-batch (FB) production cultures were seeded at multiple cell densities. Increases in seed density in the fed batch up to 8x control seed density resulted in significantly higher IVCD and titer with a 2-3 fold benefit relative to control seeded cultures. Whereas the initial increments in production seed density resulted in a linear increase in IVCD and titer, further increments showed diminishing returns. It appeared that the highest seed density production cultures were limited by nutrient supply and so richer medium and a higher feeding rate were then tested, resulting in further improvements in IVCD and titer. We also tested the effect of adapting the cells to high densities for over 50 generations prior to production cultures. For the production assessment, both the high- and standard-density adapted cells were seeded at multiple cell densities. Effect of the adaptation was modest and variable. By combining high-seed adaptation, high production culture seed densities, enriched media and high feeding rate titer yields of up to 9 g/L were achieved.