Effects of cryopreservation on recombinant CHO cell lines

Conference Dates

May 6-11, 2018


Cryopreservation provides the foundation for research, development, and manufacturing operations in the CHO-based biopharmaceutical industry. In spite of its criticality, studies are lacking that explicitly demonstrate that the routine cell banking process and potential freeze-thaw associated stress and damage during cryopreservation and recovery have no lasting detrimental effect on CHO cells. Statistics on cell-specific productivity (Qp) levels over time for GS-CHO cells generated using GS selectable marker and maintained under MSX selective pressure are also scarce. To address these gaps, we evaluated the impact of freeze-thaw on 24 recombinant GS-CHO cell lines (expressing one of three mAbs) using a series of production assays. Across our panel of cell lines, freeze-thaw did not result in any significant impact beyond the initial post-thaw passages. Production cultures sourced from cryopreserved cells and their non-cryopreserved counterparts yielded similar performance (in terms of growth, viability, and productivity), product quality (in terms of size, charge, and glycan distributions), and flow cytometric profiles (in terms of intracellular mAb expression). However, many production cultures yielded lower Qp with increasing cell age: 17 of the 24 cell lines displayed ≥20% Qp decrease within ~2-3 months. This high frequency of Qp decline for these recombinant GS-CHO cell lines underscores the continued need for careful clone selection and for understanding the underlying mechanisms for Qp loss. Because our experiments were designed to decouple the effects of cryopreservation from those of cell age, we conclusively ruled out freeze-thaw as a cause for Qp decline.

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