Bioreactor process parameters influence the N-linked glycosylation profile of the produced monoclonal antibodies. A systematic assessment of their impact is a prerequisite for providing controllability over glycosylation, one of the most critical quality attributes of therapeutic antibodies. In this study we investigated the effect of single and combined chemical and mechanical stress parameters on the glycan microheterogeneity of an IgG1 antibody using a shift-experiment procedure in batch cultures. The N-linked glycosylation profile of the murine IgG1 was found to be highly complex since it included terminal galactosylation and sialylation, as well as variable core-fucosylation. Within a pH range of 6.8 to 7.8 differences in galactosylation and sialylation of approximately 50% were obtained. Variation of dissolved oxygen tension (10-90% air saturation) resulted in a maximum variability of 20% in galactosylation and 30% in sialylation. In contrast, no significant effect on the glycosylation profile was observed when osmolarity increased from 320 to 420 mOsm/kg and sparging from 0.05 to 0.2 vvm. In this study a better understanding of bioprocess-related factors affecting critical quality attributes under the scope of QbD is provided and can bring us one step closer towards desired and targeted glycosylation for future therapeutic proteins.
Keywords: Fucosylation; Galactosylation; Glycosylation; Hybridoma cell culture; Sialylation.
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