Medical molecular farming: production of antibodies, biopharmaceuticals and edible vaccines in plants

Abstract

The use of plants for medicinal purposes dates back thousands of years but genetic engineering of plants to produce desired biopharmaceuticals is much more recent. As the demand for biopharmaceuticals is expected to increase, it would be wise to ensure that they will be available in significantly larger amounts, on a cost-effective basis. Currently, the cost of biopharmaceuticals limits their availability. Plant-derived biopharmaceuticals are cheap to produce and store, easy to scale up for mass production, and safer than those derived from animals. Here, we discuss recent developments in this field and possible environmental concerns.

Fig. 1

Costs per gram for purified immunoglobulin A produced by different expression systems. Costs for mammalian cell culture are derived from industry costs for cell culture and purification facilities. Costs for transgenic goats are derived from publicly available estimates from Genzyme Transgenics (Farmingham, MA, USA). Costs for plants compare green biomass (120.0 tonne ha⁻¹) and seed production (7.5 tonne ha⁻¹). Cost differences are based primarily on production costs, and it was assumed that purification costs and losses during purification will be the same for all systems.

Fig. 2

Alternative forms of delivery of a corn-based edible vaccine, produced by Prodigene (College Station, TX, USA). Transgenic corn kernels corresponding to a typical 1 mg dose of the B subunit of E. coli heat-labile toxin (Lt-B) (a), can be processed to generate a palatable whole corn snack of the same mass (b), or fractionated to yield an embryo or germ component in which the antigen is about six times more concentrated (c). The exact size of an administered dose depends on the expression level attained with a particular line of corn.