Mammalian cell culture continues to be the workhorse for expression of high value recombinant therapeutic protein modalities. As the requirements for the manufacturing process performance, product quality and safety continue to become more stringent, mammalian cell shear during clarification operation has become an important consideration in preventing product degradation, and in defining the clarification train design. Shearing of the cells during the clarification exposes the complex therapeutic products to intracellular enzymes, such as the reductases and proteases. Because the unit operation is conducted over many hours, and the clarified cell culture fluid is stored potentially for many days at room temperature before being loaded onto capture chromatography, the product quality can be adversely affected. Additionally, cell shear in the clarification train can produce an insoluble and soluble cell fragment “tail” that interferes with membranes and capture chromatography on a packed bed, resulting in poor purification performance.<br/>Here we present an analysis of cell shear in various harvest grade depth filters. We utilize direct (particle sizing) and indirect (enzyme release, reduction potential, product quality) analytical techniques to understand dependence of cell shear on depth filter pore size, bed loading, and pressure. Additionally, we explored alternative low shear harvesting technologies based on advanced non-porous materials. The result is that we demonstrate design strategies of clarification trains that produce low shear and, at the same time, maintain industrial scalability and robustness. These strategies insure high product quality and enable high degree of control on both soluble and insoluble contaminant clearance.

Overcoming cell shear in mAb harvests with advanced clarification train technologies and design strategies

2019 Spring National Meeting

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