Effect of Low Culture Temperature on Foreign Protein Production in Recombinant CHO Cells

Abstract

To determine the effect of low culture temperature on foreign protein production in recombinant Chinese hamster ovary (rCHO) cells, rCHO cells producing erythropoietin (EPO, LGE10-9-27) and anti-41bb antibody (LGA31-56) were cultivated at 30, 33, and 37°C, respectively. At a culture temperature lower than 37°C, cell growth was suppressed, but cell viability remained high for a longer culture period. When the culture temperature was lowered from 37°C to 33°C, more than 2.5-fold increase in the maximum EPO concentration was achieved. This enhanced EPO production at 33°C was not just because of the extended culture longevity with the decreased release of proteolytic enzymes from dead cells, but mainly because of enhanced q EPO. The q EPO at 33°C was approximately 4-fold higher than that at 37°C. Like q EPO, the relative EPO mRNA content increased by lowering culture temperature, indicating that the increased transcription level of EPO was responsible in part for the enhanced q EPO at low culture temperature. On the other hand, q Ab was not enhanced when rCHO cells (LGA31-56) producing a humanized antibody were cultivated at low culture temperature.