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2016
Journal Article
Titel
Optimization of plant cell suspension cultures for the production of recombinant proteins
Titel Supplements
Abstract
Abstract
Molecular Farming - the use of plant based systems for production of recombinant proteins - is an emerging field with a high potential impact in the biopharmaceutical industry. In the last years, plant production platforms emerged as promising alternatives to traditional expression systems, since they offer significant advantages namely in terms of safety and cost. However, a major challenge remains so that plants become truly competitive, which is to improve the low yields of product accumulation that are generally obtained. Plant cell suspension cultures are of great interest since they allow GMP compliance and an easy recovery of the secreted recombinant protein from the culture medium. Nonetheless, recombinant protein yields observed so far in plant cell suspensions are still low when compared to mammalian cell cultures. We have developed strategies for the improvement of human recombinant protein production in plant cell suspensions. Our aim is to reduce the proteolytic activity in this system, since it affects final recombinant protein yields and quality. To accomplish this goal, we studied the proteolytic profile of proteases present in our system by spiking target proteins in cell medium and analyzing the degradation pattern caused by endogenous proteolytic activity. With the addition of specific protease inhibitors, we could detect which protease classes are present in our system. Furthermore, we used activity based protein profiling (ABPP) probes to identify specific protease, within the protease class identified by the spiking assays, that is affecting the target proteins. In parallel, we performed a mass spectrometry analysis of the plant suspension media. Finally, we used N-terminal sequencing to assess the protease specific cutting sites on the target proteins. Our main goal is to establish new production plant suspension lines with reduced proteolytic activity.