title: Model-based investigation of intracellular processes determining antibody Fc-glycosylation under mild hypothermia.
abstract: Despite the positive effects of mild hypothermic conditions on monoclonal antibody (mAb) productivity (qmAb) during mammalian cell culture, the impact of reduced culture temperature on mAb Fc-glycosylation and the mechanism behind changes in the glycan composition are not fully established. The lack of knowledge about the regulation of dynamic intracellular processes under mild hypothermia restricts bioprocess optimization. To address this issue, a mathematical model that quantitatively describes Chinese hamster ovary (CHO) cell behavior and metabolism, mAb synthesis and mAb N-linked glycosylation profile before and after the induction of mild hypothermia is constructed. Results from this study show that the model is capable of representing experimental results well in all of the aspects mentioned above, including the N-linked glycosylation profile of mAb produced under mild hypothermia. Most importantly, comparison between model simulation results for different culture temperatures suggests the reduced rates of nucleotide sugar donor production and galactosyltransferase (GalT) expression to be critical contributing factors that determine the variation in Fc-glycan profiles between physiological and mild hypothermic conditions in stable CHO transfectants. This is then confirmed using experimental measurements of GalT expression levels, thereby closing the loop between the experimental and the computational system. The identification of bottlenecks within CHO cell metabolism under mild hypothermic conditions will aid bioprocess optimization, for example, by tailoring feeding strategies to improve NSD production, or manipulating the expression of specific glycosyltransferases through cell line engineering. Biotechnol. Bioeng. 2017;114: 1570-1582. © 2016 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals Inc.
authors.affiliation: Department of Life Sciences, Imperial College London, London, United Kingdom.|Centre for Synthetic Biology and Innovation, Imperial College London, London, United Kingdom.|Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Si Nga
authors.initials: SN
authors.lastname: Sou
authors.affiliation: Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Philip M
authors.initials: PM
authors.lastname: Jedrzejewski
authors.affiliation: Cell Culture and Fermentation Sciences, MedImmune, Granta Park, Cambridge, United Kingdom.
authors.forename: Ken
authors.initials: K
authors.lastname: Lee
authors.affiliation: Cell Culture and Fermentation Sciences, MedImmune, Granta Park, Cambridge, United Kingdom.
authors.forename: Christopher
authors.initials: C
authors.lastname: Sellick
authors.affiliation: Department of Life Sciences, Imperial College London, London, United Kingdom.|Centre for Synthetic Biology and Innovation, Imperial College London, London, United Kingdom.
authors.forename: Karen M
authors.initials: KM
authors.lastname: Polizzi
authors.affiliation: Department of Chemical Engineering, Centre for Process Systems Engineering, Imperial College London, London SW7 2AZ, United Kingdom.
authors.forename: Cleo
authors.identifier: 0000-0003-0213-4830
authors.initials: C
authors.lastname: Kontoravdi
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D016466:CHO Cells; D003198:Computer Simulation; D003412:Cricetulus; D006031:Glycosylation; D016695:Glycosyltransferases / Q000276:immunology*; D006361:Heating / Q000379:methods; D007141:Immunoglobulin Fc Fragments / Q000276:immunology*; D018448:Models, Immunological; D011134:Polysaccharides / Q000276:immunology*; D013696:Temperature
chemical_list: D000911:Antibodies, Monoclonal; D007141:Immunoglobulin Fc Fragments; D011134:Polysaccharides; D016695:Glycosyltransferases
keywords: CHO cells; N-linked glycosylation; flux balance analysis; galactosylation; mathematical modeling; mild hypothermia; monoclonal antibody