The production of foreign proteins from genetically modified plant cells.

While traditionally used to produce natural products, plant suspension cultures can also be utilized for the production of foreign proteins. Production of these high-value products in plant cells is an economically viable alternative to other systems, particularly in cases where the protein must be biologically active. There are several advantages to using plant cells for the large-scale production of secreted proteins. Plant cell media are composed of simple sugars and salts and are therefore less expensive and complex than mammalian media. Consequently, purification of secreted protein is simpler and more economical. Additionally, plant cell derived proteins are likely to be safer than those derived from other systems, since plant cell pathogens are not harmful to humans. In this chapter, we will review foreign protein production from plant cells. To begin, we will discuss the behavior of plant cell cultures, products produced by plant cells, protein secretion and its relationship to purification, and the performance of plant cells as compared to whole plants and other alternative hosts. After a brief discussion of gene transfer techniques, we will present strategies to overcome the limitations of protein production, including protein stabilization, novel production schemes, modeling, and scale-up considerations. To conclude, we will discuss implications for future development of this technology.