Anchorage-Dependent Growth and Recombinant Protein Production by Chinese Hamster Ovary Cells in Serum-Free Medium

Abstract

Chinese hamster ovary (CHO) cells are commonly used for the production of recombinant proteins owing to the ability of these cells to stably maintain the expression of foreign gene products which structurally and functionally resemble the naturally occurring human proteins. Serum-free culture of CHO cells is desirable since it facilitates downstream processing and recovery of products and minimizes problems associated with serum usage, such as lot-to-lot performance variability, presence of adventitious agents, and fluctuations in price and availability. We previously developed several serum-free media (SFM) formulations which support anchorage-independent growth and protein expression of CHO cells. While suspension culture of CHO cells is now an accepted method, there are many applications for which anchorage-dependent culture is desirable. Use of SFM optimized for suspension culture may result in suboptimal performance when used in anchorage-dependent culture systems. A recently developed prototype formulation, designated Adherent CHO-SFM, has-been specifically formulated to support growth and recombinant protein production using anchorage-dependent culture systems. This medium contains no bovine-derived components and has protein and endotoxin concentrations of <250 μg/ml and <1.0 EU/ml, respectively. The utility of this formulation has been demonstrated using small and larger-scale anchorage-dependent cell culture systems including tissue culture flasks, roller bottles, microcarriers and artificial capillary units. Cells cultured in Adherent CHO-SFM demonstrated biological performance which was superior to that obtained with serum-supplemented medium. Development of Adherent CHO-SFM complements our existing options for serum-free culture of CHO cells and offers the end user greater flexibility in choosing an appropriate cell culture system.