High-level expression of recombinant human soluble thrombomodulin in serum-free medium by CHO-K1 cells |
| |
Authors: | Masaaki Ogata Ken-ichi Wakita Kazuo Kimura Yasumasa Marumoto Kiyomoto Oh-i Shin Shimizu |
| |
Institution: | (1) Production Technology Research Laboratories, Daiichi Pharmaceutical Co., Ltd., 16-13, Kitakasai 1-chome, Edogawa-ku, 134 Tokyo, Japan;(2) Molecular Biology Research Laboratory, Daiichi Pharmaceutical Co., Ltd., 16-13, Kitakasai 1-chome, Edogawa-ku, 134 Tokyo, Japan;(3) Toyobo Pharmaceuticals Research Center, Toyobo Co., Ltd., 2-1-1, Katata, Otsu, 520-02 Shiga, Japan |
| |
Abstract: | Cultivation of gene-engineered Chinese hamster ovary (CHO-K1) cells that produce recombinant human soluble thrombomodulin (rsTM) was investigated to optimize conditions for high-level expression of the protein in a serum-free medium. For economic protein production, oxygenation of cultures with pure O2 permitted sufficient cell growth for high rsTM production with only 1 g/l of microcarriers and a low foetal bovine serum concentration. A longer growth phase (over 5 days) with serum was important to establish sufficient growth of this cell line on the microcarriers for subsequent serum-free culture, and to support a long-term production phase (about 2 months). In the production phase, a high glucose concentration (6.15 g/l) in the serum-free medium was very effective for prolonging the harvest cycle interval. Under these conditions, up to 100 mg/l rsTM was expressed in the conditioned medium. The rates of glucose consumption (G) and lactae production (L) were measured periodically and their ratio (L/G ratio) correlated with rsTM productivity. When the average L/G ratio was lower, reflecting a lower lactate production rate due to appropriate oxygenation of the culture, the specific rsTM production rate increased. Thus it may be possible to estimate protein productivity from L/G ratios calculated from the glucose and lactate measurements.
Correspondence to: M. Ogata |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|