RACHEL MARTIN, HOST:
Companies trying to make a vaccine for COVID-19 are trying a variety of approaches. Most involve laboratories capable of sophisticated biotechnology, but NPR's Joe Palca has this report about one approach for creating a vaccine which starts in a greenhouse.
JOE PALCA, BYLINE: Vaccines essentially work by tricking the immune system into thinking it's seen a virus so it can fight it off if the real McCoy ever shows up. Bruce Clark is CEO of Medicago, a Canadian biotech company. He says his company put something called a viruslike particle into its COVID-19 vaccine.
BRUCE CLARK: To all intents and purposes, it looks like a virus. So when it presents to the body, it looks and generates a response like a virus, but it has no genetic material inside, so it's not infectious.
PALCA: But the curious thing about this genetic material-free viral imposter is that it's made in a plant - to be specific Nicotiana benthamiana, a close relative of the tobacco plant, a plant they grow in a greenhouse. And Medicago isn't the only company trying to make a vaccine from plants. Hugh Haydon is president of Kentucky Bioprocessing. He says, to make their vaccine, they start with seeds and grow the tobacco plants in the greenhouse for approximately 25 days.
HUGH HAYDON: And on that prescribed date, we take the plant and we dip it into an agrobacterium.
PALCA: Agrobacteria are microorganisms that infect plants, and in this case, they've been modified to contain instructions for making a protein from the coronavirus. The plants take up those instructions.
HAYDON: On the seventh day, we harvest the plant, go through an extraction and purification process, and at the end of the cycle, we have 99.9% pure protein.
PALCA: Haydon says a separate set of plants produces a tiny particle for packaging the viral protein.
HAYDON: Once each of those components has been manufactured and purified separately, we chemically attach them to each other.
PALCA: Haydon says the result is something that can be injected into a human as a vaccine and will prompt an immune response that should, in theory, protect someone from dying from COVID-19. The irony that tobacco, a plant that has caused so much illness and death, might be used to save lives in a pandemic isn't lost on Jim Figlar. He's executive vice president for research and development for R.J. Reynolds Tobacco, the company that owns Kentucky Bioprocessing.
JIM FIGLAR: Yes, there's obvious irony there, Joe. If you wanted to be cynical about it, you can think cynically about it. But we tend to think of it as - look; at the end of the day, the tobacco plant in and of itself is still just a plant.
PALCA: Kentucky Bioprocessing's COVID-19 vaccine won't be ready for initial testing in humans for several weeks yet. Company president Haydon knows there are many other vaccines further ahead in development, but he says COVID-19 won't be the last pandemic.
HAYDON: There are going to be other public health challenges, and the more that we can learn as a company, the better prepared we are for what comes next.
PALCA: Plant biologist Kathleen Hefferon agrees plants could play an important role in the future of medicine.
KATHLEEN HEFFERON: There's lots of examples of plant-made versions of therapeutic proteins, and so this is just another place where I think plants can make their mark.
PALCA: Out of the greenhouse and into the clinic.
Joe Palca, NPR News.
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