Our monoclonal antibody platform process was applied for the production of a recombinant enzyme fusion protein in a GS-CHO cell line.  Process development objectives for this project included increased productivity over the existing DG44-based process while maintaining comparable product quality attributes. Initial characterization of GS-CHO-produced material identified several product quality attributes to optimize: total enzyme activity, glycosylation profiles, sialic acid content and product fragmentation, as seen by SDS-PAGE.  To address these, we investigated the impact of zinc, calcium and magnesium supplementation, galactose supplementation, bioreactor pH and temperature and viability at harvest.Metal ion supplementation had a profound effect on total enzyme activity, and an optimal feeding schedule was identified using a microbioreactor system.  Galactose supplementation was able to modulate glycosylation profiles and increase sialic acid content, while pH setpoint and harvest criteria were also found to impact sialic acid content.  Finally, manipulation of the bioreactor temperature could be used to control product fragmentation.These experiments allowed us to narrow the range of operating conditions, and subsequently apply these during cell line selection.  Process levers identified here were used to redefine our platform for non-antibody products.

Product quality considerations for recombinant enzyme production

245th National Meeting (2013)

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