The increasing usage of monoclonal antibodies (mAbs), often expressed in Chinese Hamster Ovary (CHO) cells, for human therapy, has led to a focus on rational approaches to speed the development of cost-effective and highly productive cell lines. Understanding the process physiology of industrial CHO cell lines is important to making significant progress in cell line and culture development. In this study, which was underpinned by the supply of several industrial CHO cell lines by an industrial collaborator (Lonza Biologics) and newly developed industrial CHO media by another industry partner (Thermo Fisher Life Sciences), the effects of several process variables including different clones of cells, passage number, scale of culture, culture medium, feed supplements and culture modes (batch and fed-batch) on cell line physiology were investigated. GS-CHO 42 cell lines a high monoclonal antibody producer with low passage number (4) were observed to give better results compared to a less productive cell lines and higher passage numbers. In addition, three commercially available, chemically defined CHO cell culture media (CD-CHO, CD-OPTICHO and Dynamis) and two different types of feed supplements, CHO CD Efficient Feed A (EFA) and CHO CD Efficient Feed B (EFB) were evaluated in batch culture and fed-batch culture using the GS-CHO 42 cell line passage number 4. Cell culture in shake flasks and bioreactors showed clear effects of culture system on process physiology. In contrast, concentrated feed supplements did not help to increase the cell concentration and antibody titre. Amongst the three media tested, CD-CHO medium was found to be the best culture medium for GS-CHO 42 passage number 4 based upon the cell density, viability and Immunoglobulin (IgG) titre produced.A metabolomics study was carried out on samples from these cultures to observe the metabolic profiles under different culture conditions. Statistical analysis with Principal Component Analysis (PCA) and Orthogonal Projections to Latent Structures Discriminant Analysis (OPLS-DA) were performed using SIMCA version 14.0 to view the underlying global structure of the expression data. The results show that different metabolites were present under different culture conditions (different culture medium, scales and mode of culture) and were associated with different physiological behaviour of GS-CHO cell cultures. By using the results of this study, several bioprocessing strategiesincluding medium improvement, feeding strategy and downstream processing can be potentially implemented to achieve efficient CHO culture system. Nevertheless, more detailed studies are warranted to confirm and complement the existing information. The results in this work show how important process related information can be obtained with univariate and multivariate process analysis methods. Especially in cell culture process development, which is characterized by lengthy run times, a large number of influential and mutually interacting factors, as well as high-cost raw materials and process analytics, multivariate data analysis represents an attractive and versatile tools in process development.
|Date of Award||14 Sep 2018|
- University Of Strathclyde
|Sponsors||University of Strathclyde|
|Supervisor||Brian McNeil (Supervisor) & Linda Harvey (Supervisor)|