Biopharmaceuticals plants expressing

The amount of vaccine or therapeutic protein produced in a plant can reach industrial-scale levels. The typical yield of biopharmaceuticals produced in a plant-based system is 0.1%-1.0% of total soluble protein (Twyman et al., 2003). This value is competitive with other expression systems therefore, a plant expression platform for biopharmaceuticals is economically viable. As an example, one bushel of maize can produce as much avidin as one ton of chicken eggs but at 0.5% the cost. 

Safflower In safflower plants expressing biopharmaceuticals, the protein of interest is fused to oleosin, the protein that forms oil bodies within the safflower seeds. The seeds can be crushed and the oil bodies then easily purified by centrifugation. This oleosin-fusion protein system was first developed by SemBioSys Genetics, Inc., in safflower or oilseed rape. 

The EPA is involved in the regulation process if the transgenic plant expresses a pest- or herbicide-resistant engineered trait in addition to a biopharmaceutical. 

Quality control of plant-made biopharmaceuticals for commercial use includes the development of a seed bank based on the transgenic plant expressing the therapeutic product, the development of a population of plants grown from a seed bank, the harvesting of these plants, and their subsequent subjection to an extraction and purification process similar to... 

Tackaberry ES, Dudani AK, Prior F, et al. Development of biopharmaceuticals in plant expression systems cloning, expression and immunological reactivity of human cytomegalovirus glycoprotein B (UL55) in seeds of transgenic tobacco. Vaccine, 1999 17(23/24) 3020-3029. 

Now we shift gear slightly and switch from transgenic animals to transgenic plants. ICON Genetics in Halle, which I consider as one of the leading experts in plant expression, use tobacco for the expression of biopharmaceutical proteins. Professor Yuri Gleba from the Ukrainian Academy of Sciences is one of the early pioneers of biopharmaceutical production in plants, with over 30 years of experience, and also founded the International Insti-... 

J. Knablein, Biotech A New Era in the New Millennium - From Plant Fermentation to Plant Expression of Biopharmaceuticals, PDA International Congress, Prague, Czech Republic, 2003. 

In this review, we focus on the use of plant tissue culture to produce foreign proteins that have direct commercial or medical applications. The development of large-scale plant tissue culture systems for the production of biopharmaceutical proteins requires efficient, high-level expression of stable, biologically active products. To minimize the cost of protein recovery and purification, it is preferable that the expression system releases the product in a form that can be harvested from the culture medium. In addition, the relevant bioprocessing issues associated with bioreactor culture of plant cells and tissues must be addressed. 

As indicated in Table 2.1, most of the promoters used in plant tissue culture have been based on the constitutive cauliflower mosaic virus (CaMV) 35S promoter. In contrast, inducible promoters have the advantage of allowing foreign proteins to be expressed at a time that is most conducive to protein accumulation and stability. Although a considerable number of inducible promoters has been developed and used in plant culture applications, e.g. [32-37], the only one to be applied thus far for the production of biopharmaceutical proteins is the rice a-amylase promoter. This promoter controls the production of an a-amylase isozyme that is one of the most abundant proteins secreted from cultured rice cells after sucrose starvation. The rice a-amylase promoter has been used for expression of hGM-CSF [10], aranti-trypsin [12, 29, 38, 39] and human lysozyme [30]. 

This chapter illustrated the broad spectrum of uses for plant-derived vaccines and therapeutic proteins. Many of the biopharmaceuticals listed in this chapter were developed in transgenic tobacco or potato plants. While tobacco is not ideal for the expression of vaccine proteins nor is raw potato ideal for oral consumption, they are both relatively easy to work with and have been well characterized, making them useful for proof-of-concept studies. The use of plants for production systems and delivery vehicles holds great promise for future biopharmaceutical development. Proteins can be produced in plants while remaining biologically functional they can be scaled up for large production and purified inexpensively and with relative ease. The following chapters describe the many attributes of plant-made biopharmaceuticals in more detail. 

A Plant Viral Expression Vectors and Production of Biopharmaceuticals in Plants... 

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