Environmental stimuli on the soluble expression of anti-human ovarian carcinoma x anti-human CD3 single-chain bispecific antibody in recombinant Escherichia coli

摘要

The influences of different environmental stimuli on the soluble expression of anti-human ovarian carcinoma x anti-human CD3 single-chain bispecific antibody in Escherichia coli were examined to improve its yield. Often, it was found that the amount ratio of the inclusion body fraction to the soluble fraction of the recombinant protein varied greatly with the changes of environmental conditions in fermentation process. Wherefore, an improved strategy based on various undercritical stimuli, including such environmental factors as temperature-shift, pH-shift and repetitious pH-shift, was employed to enhance the soluble expression of the target protein. As a result, an optimal factor-shift process was determined and the soluble yield of the target protein increased by 82.9% (from 68.9 to 126.6 mg protein/g DCW) in flask fermentation compared with the result cultured at 30°C. And the high soluble expression level was also obtained in a 3.7 L fermentor based on this strategy. This improved strategy that factor-shifts under undercritical environmental stimuli improve the soluble expression of exogenous proteins in recombinant E. coli may become a new alternative besides the genetic engineering considerations.