Elucidating the effects of pH shift on IgG1 monoclonal antibody acidic charge variant levels in Chinese hamster ovary cell cultures
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- 作者：Panpan Xie ; Huijie Niu ; Xinning Chen…
- 关键词：Acidic charge variants ; IgG1 monoclonal antibody ; Disulfide bond reduction ; Galactosylation ; Deamination ; Liquid chromatography mass spectrometry
- 刊名：Applied Microbiology and Biotechnology
- 出版年：2016
- 出版时间：December 2016
- 年：2016
- 卷：100
- 期：24
- 页码：10343-10353
- 全文大小：
- 刊物类别：Chemistry and Materials Science
- 刊物主题：Microbiology; Microbial Genetics and Genomics; Biotechnology;
- 出版者：Springer Berlin Heidelberg
- ISSN：1432-0614
- 卷排序：100
文摘
Charge variants, especially acidic charge variants, in recombinant monoclonal antibodies are critical quality attributes, which can affect antibodies’ properties in vitro and in vivo. Meanwhile, charge variants are cumulative effects of various post-translational modifications and chemical degradations on antibody. In this work, to investigate the effect of lowering culture pH in the stationary phase on acidic charge variant contents in fed-batch cultures and its mechanism, cell culture experiments in 2-L bioreactors were firstly performed to explore the changes in the charge distribution under the pH downshift condition using weak cation exchange chromatography. It is found that acidic charge variant contents were significantly decreased by pH downshift. Then, to reveal the mechanism by which the content of acidic charge variants is reduced under pH downshift condition, the variation of post-translational modifications and chemical degradations under the pH downshift condition was explored. Meanwhile, the structure of the acidic charge variants was characterized. Several analysis experiments including size exclusion chromatography, capillary electrophoresis-sodium dodecyl sulfate under non-reducing conditions, tryptic peptide map, and reduced antibody mass were applied in this study. The results show that the mechanism by which the content of acidic charge variants is reduced is that the contents of disulfide bond reduction, galactosylation, and asparagine deamination of the HC-N388 in the Fc domain were reduced by pH downshift.