Adaptation of Chinese Hamster OvaryCells to High Potassium Ion-ContainingMedium for Enhancement of Follicle-Stimulating Hormone Production

In this study, a suspension culture of recombinant Chinese hamster ovary (CHO) cells producing follicle-stimulating hormone (FSH) was used to investigate the effects of potassium ion (K+) on cell growth and FSH production. Cell growth was significantly suppressed at a K+ concentration higher than 60 mM, but specific FSH productivity (qFSH) was enhanced more than 2-fold compared to the value obtained at 4 mM K+. In an attempt to alleviate the cell growth suppression at a high K+ concentration, the cells were adapted at 60 mM K+ in a repeated batch mode. During adaptation, the growth rate increased from 0.010 to 0.020 h-1, and qFSH also gradually increased and reached 11.1 ng/(106 cells h), which was even higher than that of the unadapted cells at 60 mM K+. The adapted cells showed a 2.6-fold increase in maximum FSH titer at 80 mM K+ compared to the unadapted cells at 4 mM K+. Taken together, these results demonstrate the potential of using culture media containing cells adapted to high K+ concentrations, for the enhancement of recombinant protein production. KCI Citation Count: 7