Maintenance of High Viability During Direct Transition of CHO-K1 Cell Growth from 10% to 0% Serum; No Adaptation Required
Historically, serum or serum-fractions have had a universal applications in cell culture. It is an indispensable supplement for classical cell culture media (CCCM) because CCCM were developed containing serum. Utilizing these media to grow cells without the addition of serum cannot be easily achieved. In addition, the CCCM were developed primarily to support the growth of low density adherent cells in t-flasks where cell growth is limited by surface area. The usual method to grow cell without serum is to adapt the cells to the CCCM by decreasing serum levels in a step-wise fashion. To decrease the serum levels, these cells must maintain a reasonable cell viability and density. It is very important to keep in mind the ultimate objectives when adapting cells to a serum-free environment. If the secretion of a large amount of a specific protein is the final goal, monitoring the level of secreted protein while adapting the cells to serum-free medium becomes very critical. With decreasing serum levels, the number of viable cells tends to be low, making the adaptation process laborious and time consuming. Furthermore, the adapted cells are in CCCM that cannot effectively support the desired high density suspension culture. Basically, there is no universal serum-free CCCM applicable to all cell lines. Customized media that has been specifically tailored to each cell line is required. The goal was to develop a defined serum-free medium that would support the direct transition of serum-supplemented adherent CHO-K1 culture to serum-free suspension (spinner) culture. An optimized chemically defined medium (COM), ProCHO4-CDM, that achieves high density cell growth for the Chinese Hamster Ovary (CHO) cell line, was compared to two commercially available serum-free CHO media.
KeywordsChinese Hamster Ovary Chinese Hamster Ovary Cell Line Decrease Serum Level Dhfr Gene Spinner Culture
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