The processinvolves growing tobacco plants, not in the acres of fields earmarked bytobacco companies for their cigarettes, but in a controlled environment in agreenhouse, for six weeks. Then, the leaves of the plants are injected orinfused with a plant bacterium that carries a valuable payload — the genes forthe antibodies that can bind to and neutralize the Ebola virus. The plant cellstreat the new genes as one of their own, and start making the antibody. Ittakes about 14g of these antibodies to treat a patient and to produce that muchrequires around 78 tobacco plants and about seven to 10 daysWhy plants? Thetime it takes to grow a plant is less time than it takes to geneticallyengineer a mouse or other rodent to produce human antibodies, which is how suchproducts have been made in the past. It’s also less expensive. Plant-basedmanufacturing represents a promising new way of producing drugs that could cutthe time it takes to bring critical medications, such as a flu vaccine during apandemic, to a large number of people.
Researchers have used the technology todevelop a vaccine against norovirus, the infection that plagues cruise ships,for example, that is being tested now.The molecular machinery of plantcells is closely related to that of animal cells. Thus, plant cells are able tosynthesize and process relatively complex biologics.
Indeed, GEGenetically Engineered plants have been shown to be able to produce human antibodies (immunoglobulins).Such so-called “plant bodies”appear to have the same biochemical properties as antibodies produced in animalcell cultures.The first proof of concept forfunctional antibody production in plants was provided in 1989, when twotransgenic tobacco plants, each expressing light or heavy chains, were producedby Agrobacterium-mediated transformation of tobacco leaf discs. Crossing thesetwo transgenic tobacco lines led to the expression of assembled functional IgGantibodies, accumulating up to 1.
3% of total soluble protein. From then on,numerous antibodies and other proteins have been expressed in plants,demonstrating that plants can express and assemble components into functional,complex multimeric