Department of Chemical Engineering, Imperial College London, London, United Kingdom.
PLoS One. 2022 Mar 23;17(3):e0265886. doi: 10.1371/journal.pone.0265886. eCollection 2022.
Monoclonal antibodies (mAbs) have been extensively studied for their wide therapeutic and research applications. Increases in mAb titre has been achieved mainly by cell culture media/feed improvement and cell line engineering to increase cell density and specific mAb productivity. However, this improvement has shifted the bottleneck to downstream purification steps. The higher accumulation of the main cell-derived impurities, host cell proteins (HCPs), in the supernatant can negatively affect product integrity and immunogenicity in addition to increasing the cost of capture and polishing steps. Mathematical modelling of bioprocess dynamics is a valuable tool to improve industrial production at fast rate and low cost. Herein, a single stage volume-based population balance model (PBM) has been built to capture Chinese hamster ovary (CHO) cell behaviour in fed-batch bioreactors. Using cell volume as the internal variable, the model captures the dynamics of mAb and HCP accumulation extracellularly under physiological and mild hypothermic culture conditions. Model-based analysis and orthogonal measurements of lactate dehydrogenase activity and double-stranded DNA concentration in the supernatant show that a significant proportion of HCPs found in the extracellular matrix is secreted by viable cells. The PBM then served as a platform for generating operating strategies that optimise antibody titre and increase cost-efficiency while minimising impurity levels.
单克隆抗体 (mAb) 因其广泛的治疗和研究应用而得到广泛研究。通过细胞培养培养基/饲料的改进和细胞系工程来提高细胞密度和特定 mAb 的生产力，从而提高 mAb 的效价。然而，这种改进将瓶颈转移到下游纯化步骤。上清液中主要细胞来源杂质、宿主细胞蛋白 (HCP) 的更高积累除了增加捕获和抛光步骤的成本外，还会对产品完整性和免疫原性产生负面影响。生物过程动力学的数学建模是一种提高工业生产速度和降低成本的有价值工具。在此，建立了一个基于体积的单级群体平衡模型 (PBM)，以捕获补料分批生物反应器中中国仓鼠卵巢 (CHO) 细胞的行为。该模型使用细胞体积作为内部变量，在外周环境中捕获生理和轻度低温培养条件下 mAb 和 HCP 积累的动力学。基于模型的分析和上清液中乳酸脱氢酶活性和双链 DNA 浓度的正交测量表明，细胞外基质中发现的大量 HCP 是由有活力的细胞分泌的。然后，PBM 作为一个平台，用于生成操作策略，优化抗体效价，提高成本效益，同时最大限度地降低杂质水平。
