Effect of Low Culture Temperature on Specific Productivity and Transcription Level of Anti‐4–1BB Antibody in Recombinant Chinese Hamster Ovary Cells

Lowering the culture temperature has been suggested as a useful tool for improving the production of recombinant proteins in Chinese hamster ovary (CHO) cells. In an effort to improve anti-4–1BB antibody production in recombinant CHO (rCHO) cells, rCHO cells producing anti-4–1BB antibody (LGA31–56) were cultivated at three different temperatures, 30, 33, and 37 °C. Lowering the culture temperature led to suppressed cell growth, cell cycle arrest in G0/G1 phase, and improved cell viability for a longer period. However, antibody production and qAb were not increased at low culture temperature. The maximum antibody concentration and qAb at 37 °C were 110.6 ± 2.6 μg mL-1 and 0.43 ± 0.03 μg (106 cells h)-1, respectively, whereas those at 30 °C were 28.3 ± 3.8 μg mL-1 and 0.44 ± 0.07 (106 cells h)-1, respectively. Northern blot analysis revealed that lowering the culture temperature did not increase the transcription level of heavy and light chains. These results were quite in contrast with the improved production of erythropoietin, which is expressed in the same CHO host and driven by the same CMV promoters, by lowering the temperature. Taken together, the results obtained imply that the beneficial effect of low culture temperature on recombinant protein production in rCHO cells is cell-line-specific.