Plant-Based Vaccines
Vaccines are arguably one of the greatest scientific discoveries in human history. But the noble pursuit of wiping out devastating diseases like smallpox, polio or diphtheria is tricky business. It’s costly and time consuming. After all, vaccines don’t grow on trees . . . yet.
Vaccines help “train” the body’s immune system to defend itself against infections by introducing it to parts of a pathogen. These parts are called “antigens.” They are usually proteins and, with the exception of RNA and DNA vaccines, they are manufactured inside of cultured cells or eggs. This method of vaccine production can take 4-6 months, but scientists are learning that plants can help speed up production, drastically.
Medicago Inc., a company based in Quebec, Canada is using a species of tobacco to farm molecules. Through a process known as “transient-expression,” they can use the leaves of the tobacco plants to express staggeringly high levels of proteins, which can then be extracted and purified. The process takes 6-8 days.
In order to make a plant-based vaccine, the company uses the plants to produce something called “virus-like particles." These are empty particles, mere shells of protein with an engineered antigen attached. They are based on plant viruses, which is good because . . . I mean . . . when’s the last time you got infected by a plant virus? The virus-like particles also lack any genetic material, meaning they’re completely non-infectious, so you AND your houseplants are safe.
Medicago Inc. is in clinical trials for a quadrivalent influenza vaccine, that means it protects against four different strains of the flu. There is a strong chance it will become the first approved, plant-derived vaccine for human use. And if you’re wondering, “Can we get these people to make a COVID-19 vaccine?” The answer is “They already have.” They developed a plant-based COVID-19 vaccine in just 20 days and it’s just started clinical trials.
Plant-based vaccines offer hope for a future of rapid and cost-effective vaccine production and a world more inclusive of people with egg allergies.
Works Cited:
“How plants could produce a COVID-19 vaccine.” nature.com, 2020, https://www.nature.com/articles/d42473-020-00253-2.
“Plant Derived Vaccines.” nature.com, 2018. https://www.nature.com/articles/d43747-020-00537-y.
Santi, Luca, Zhong Huang, and Hugh Mason. "Virus-like particles production in green plants." Methods 40.1 (2006): 66-76.
Brian Rutter, PhD, is the cofounder of Thing in a Pot Productions and a postdoctoral researcher in plant biology at Indiana University. Subscribe to our newsletter to receive our “Things About Things – Odd Facts About Plants” and video production tips in your inbox every month!