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Scientists Are Programming Tobacco Plants to Fight the Next Ebola Outbreak

For once, tobacco could actually help us out.
September 22, 2014, 4:05pm

Pandemics never turn out well for Patient Zero. If you're among the first infected in a new outbreak, just about the only thing you've got going for you nowadays is a possible cameo in the medical textbooks.

That's because, for aggressive infections, thousands may die before the achingly slow process of drug development turns up any real results. Enter plantibodies. A combination of genetic engineering and plant biotechnology, plantibodies are antibody-based drugs grown inside living plants. Plant-based processes have been touted as cheaper and safer than conventional drug development.

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And faster. Much, much faster.

Last month, when Ebola began tearing across West Africa in earnest, researchers at Mapp Biopharmaceutical injected DNA into tobacco plants and coaxed them into growing a batch of promising plantibodies. They delivered their experimental drug, ZMapp, in record time. That kind of speed could help scientists concoct life-saving drugs before an outbreak gets out of hand.

"In infectious disease response, speed really does matter," Robert L. Erwin, President of iBio Inc., a Delaware-based biotechnology firm that specializes in plant-based pharmaceuticals, told me. "With plants, you can respond to a crisis much faster."

Racked tobacco plantibodies in semi-robotic hydroponic grow. Photo: Fraunhofer/iBIoLaunch

Growing drugs inside plants is a refreshing, green twist on a long-standing, less glamorous method. Conventional antibody-based drugs are cooked inside Chinese hamster ovary cells ( yes, really) and cultivated in giant metal vats. The process can take months and the costs of building facilities to host the research can be astronomical.

According to data provided by iBio Inc., a 140,000 square foot Novartis facility recently cost $600 million to build, while iBio's own, smaller facility cost $68 million. iBio claims that its less expensive, smaller facility could actually produce more flu vaccines per year than the pharma giant.

The process of plantibody development is a spin on classic immunology. Antibodies, highly-specific protein conglomerates that make a beeline through the body to reach specific targets, are isolated from humans or mice. Scientists then capture a promising antibody's DNA sequence and load it onto a virus, which infects the plant with genetic information and forces it to grow more antibodies.

The plants are harvested much like you would harvest a plant for salad.

Tobacco plants are the likeliest victims. Grown hydroponically in vast, leafy laboratories, tobacco makes a hardy, fast-growing host. Within 2-7 days, tobacco plants can produce enough plantibodies for a substantial harvest.

"At the beginning, the plants are harvested much like you would harvest a plant for salad," Erwin said. "You're harvesting leaves, grinding them up, and then centrifuging them into a green, smoothie-like liquid."

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This process cuts out many of the expensive and time-consuming aspects of conventional antibody production. Antibodies grown outside of tobacco plants, for instance, demand large volumes of sterile culture media solutions and regular maintenance for the fragile genes in each cell line.

Keeping tobacco plants primed and ready to grow is far simpler. "Plants can be continuously available via semi-robotic hydroponic operations on a 'standby' basis," Erwin explained.

Tobacco plant seeder. Photo Fraunhauer/iBioLaunch

Despite the fact that experts say plantibodies are faster and cheaper to grow, plant-derived drugs remain a rarity in the marketplace. Pharmacies are full of conventional antibody therapies, which treat cancers and autoimmune conditions from arthritis to Crohn's disease. On the plantibody front, progress has been slower.

About ten years ago, Planet Biotechnology, a private company in California, produced a plantibody to prevent tooth decay that ultimately gained approval in Europe. In 2012, the FDA approved Elelyso, a carrot-based drug that treats Gaucher disease.

Since then, the biggest news on the plantibody front is ZMapp, the controversial drug that may treat Ebola infections. The cocktail of three plantibodies, derived from tobacco plants, is believed to interact with Ebola on the molecular level, disabling the virus by binding to it specifically. The treatment, however, is still experimental. Too few humans have received ZMapp to determine whether or not it is safe and effective.

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Major drug companies have been slow to adopt plant-based techniques. One reason for this may be the hefty investments that have already been made into conventional pharmaceutical methods.

"The technology in use now is very established and extremely efficient," Michael Kamarck, a biotechnology industry consultant and former manufacturing executive at Merck, told Reuters last month. "The big companies have made those investments and adopted those systems."

That's big pharma talk for if it ain't broke, don't fix it. Still, for a speedy and inexpensive response to the next big outbreak, it is not hard to imagine the pharmaceutical industry turning to plants in a pinch.

"In an emergency response situation, plants would yield meaningful drug quantities in days, whereas mammalian cell culture facilities would likely require months to achieve the same level of production," Erwin said.

For Patient Zero, that's a difference that counts.