title: Enhanced CHO cell-based transient gene expression with the epi-CHO expression system.
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.
authors.affiliation: The University of Queensland, Australian Institute for Bioengineering and Nanotechnology, Brisbane, QLD, 4072, Australia. g.codamo@uq.edu.au
authors.forename: Joe
authors.initials: J
authors.lastname: Codamo
authors.forename: Trent P
authors.initials: TP
authors.lastname: Munro
authors.forename: Benjamin S
authors.initials: BS
authors.lastname: Hughes
authors.forename: Michael
authors.initials: M
authors.lastname: Song
authors.forename: Peter P
authors.initials: PP
authors.lastname: Gray
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal / Q000235:genetics / Q000378:metabolism*; D015153:Blotting, Western; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D004591:Electrophoresis, Polyacrylamide Gel; D008081:Liposomes; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D000911:Antibodies, Monoclonal; D008081:Liposomes; D011994:Recombinant Proteins