Abstract
Transient gene expression systems in mammalian cells continue to grow in popularity due to their capacity to produce significant amounts of recombinant protein in a rapid and scalable manner, without the lengthy time periods and resources required for stable cell line development. Traditionally, production of recombinant monoclonal antibodies for pre-clinical assessment by transient expression in CHO cells has been hampered by low titers. In this report, we demonstrate transient monoclonal antibody titers of 140 mg/l with CHO cells using the episomal-based transient expression system, Epi-CHO. Such titers were achieved by implementing an optimized transfection protocol incorporating mild-hypothermia and through screening of a variety of chemically defined and serum-free media for their ability to support elevated and prolonged viable cell densities post-transfection, and in turn, improve recombinant protein yields. Further evidence supporting Epi-CHO’s capacity to enhance transgene expression is provided, where we demonstrate higher transgene mRNA and protein levels of two monoclonal antibodies and a destabilized enhanced green fluorescent protein with Epi-CHO compared to cell lines deficient in plasmid DNA replication and/or retention post-transfection. The results demonstrate the Epi-CHO system’s capacity for the rapid production of CHO cell-derived recombinant monoclonal antibodies in serum-free conditions.
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Acknowledgments
The authors would like to thank Karen Hughes for her critical feedback in the preparation of this manuscript, Kannan Kaliappan for technical assistance with media adaptation, the NCRIS Biologics Facility at the AIBN, and Robert Simpson from the Real-time PCR Facility at The University of Queensland.
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Codamo, J., Munro, T.P., Hughes, B.S. et al. Enhanced CHO Cell-Based Transient Gene Expression with the Epi-CHO Expression System. Mol Biotechnol 48, 109–115 (2011). https://doi.org/10.1007/s12033-010-9351-9
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DOI: https://doi.org/10.1007/s12033-010-9351-9