By Zhang Linyu, Xiao Hui, and Wang Xuebin, Corning Incorporated, Corning Life Sciences Asia Technology Center
Mammalian cells are a well-established system for the expression of biologically active recombinant proteins and antibodies that possess appropriate post-translational modifications.1 Stable expression technologies have yielded kilograms of protein from mammalian cells.2 However, some major disadvantages of stable expression technology are the time, resources, and costs associated with the generation of a high-producing cell line.3 Therefore, there is a need for more rapid and less expensive approaches for recombinant protein production. Transient gene expression is a popular method for efficient production of recombinant proteins in mammalian cells. With optimization and scale-up, transient transfection in mammalian cells can improve the throughput and speed of production of functional human proteins.3
Chinese hamster ovary (CHO) cell suspensions are well-suited for high-yield production of recombinant proteins. The Gibco ExpiCHO™ Expression System uses a CHO-S cell line, expression media designed for high-density transfection, expression enhancers, feeds, and a high-efficiency transfection reagent to maximize protein expression levels.4
The Corning 5L PETG Erlenmeyer flask is designed for scaleup suspension cultures with space efficiency in mind, thus supporting CHO cell line expansion and recombinant protein expression. The PETG material is free of 3,5 binitro-BPA leachate which can inhibit cell growth providing optimized culture conditions for sensitive suspension cell lines. The 5L shape has also been optimized for increased gas exchange compared to the more traditional Erlenmeyer flask designs. In this study, we describe a method for the transient transfection of CHO cells in Corning 5L Erlenmeyer flasks, which allow for enhanced recombinant protein production. We also compared the performance of the Corning 5L PETG Erlenmeyer flask to 5L polypropylene (PP) flasks from a comparable brand.