(820h) Modulation and Modeling of Monoclonal Antibody N-Linked Glycosylation

Mammalian cells represent the state-of-the-art expression system for modern monoclonal antibody (mAb) manufacturing processes due to their ability of posttranslational modifications of the desired product such as N-linked glycosylation. Although these modifications are required to obtain a high efficacy, bioavailability or even a proper folding of the protein, the complex and heterogeneous nature of glycosylation has caused problems to identify the most active form(s) and the development of cell culture processes which produce a desired pattern. It has been shown that cell culture conditions such as pH, C-sources and by-products can have a significant impact on N-linked glycosylation and therefore a distinct product quality can be adjusted with optimized process parameters and feeding strategies. However, by-product accumulation, in particular increasing ammonia concentration¹ and a decreasing availability of nucleotide sugar donors influence the intracellular glycosylation mechanism significantly².

In order to produce a constant glycosylation pattern during a fed-batch process, experiments with different operating parameters and various feeding strategies were carried out in a micro bioreactor system which produced mAbs with different glycosylation profiles. Measurements of basic metabolites and intracellular nucleotide sugars were used to tune a mathematical model to describe the resulting quality attributes based on a dynamic mathematical model of N-linked glycosylation³. This combined experimental and modeling approach could serve not only as a quality by design instrument during bioprocess development but can also be used to define an engineering design space with process boundaries for large scale production.

Literature

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(2)      Kochanowski, N.; Blanchard, F.; Cacan, R.; Chirat, F.; Guedon, E.; Marc, A.; Goergen, J.-L. Analytical Biochemistry 2006, 348, 243–251.

(3)      Jimenez Del Val, I.; Nagy, J. M.; Kontoravdi, C. Biotechnology Progress 2011, 44, 1–44.