HAIRY TIMES Putting tobacco to good use
CORONAVIRUS: MAY PLAY PART IN THE CURE
Plant grows quickly, has a weakened immune system and gives dependable test results.
Contributing to millions of deaths every year globally, tobacco has a poor reputation, and rightfully so. The plant, however, also has a healing side. Cape Bio Pharms, a spin-off company of the Biopharming Research Unit (BRU) at the University of Cape Town (UCT), is using a distant cousin, Nicotiana benthamiana, as a bioreactor to produce antibodies and antigens.
These are crucial to develop new biomedical solutions to cure, prevent and detect a variety of diseases, including the novel coronavirus Sars-CoV-2, which causes Covid-19.
The company was launched in 2018 with funding from the Technology and Human Resources for Industry Programme.
For the past two years, the leafy plants have been grown in a state-of-the-art hydroponic grow room in Ndabeni, Cape Town, with the purpose of infiltrating them with bacterial cultures at six weeks old.
The plants then start producing the required biologics, or medically relevant proteins, which are extracted three to seven days later.
“Scientists will use these to study particular bacteria or viruses, with the intention of developing solutions to detect, combat and prevent them,” said cofounder and chief scientific officer Tamlyn Shaw.
The reason for tapping into Nicotiana benthamiana plants, which the BRU lab has been using for more than 20 years for a multitude of purposes, is because of its strength, ability to grow quickly and weakened immune system.
“It is the model plant for this type of work as it doesn’t fight against the infection as much as other plants,” Shaw said, noting it was a desert plant, native to Australia. “To survive, it had to throw away a lot of its immunity. We are taking advantage of that.”
What makes plant-made antibodies interesting is that the process from seed to extraction takes weeks, which is significantly faster than manufacturing conventional mammalian reagents.
“That can take months to half a year,” said Professor Ed Rybicki, BRU virologist and director.
Each batch of plant-based reagents is derived from the same genetic construct, which didn’t apply to animal-made antibodies.
“Consistency helps life scientists produce dependable biomedical test results, which fast tracks the development of new medicines, vaccines and diagnostics, helps curb pandemics faster and saves lives. As we are seeing now with Covid-19, time is essential when fighting outbreaks.”
Another key time-related advantage is the scalability of plant-based systems.
“When scientists need more antibodies, we simply grow more plants. Scaling takes weeks, not months,” Shaw says.
The production of safe, reliable, and reproducible biologics in SA and making them available to local life scientists allows them to strengthen their position in the global biotech innovation scene.
“At the moment, our scientists rely on the imports of these products, which costs a lot of time and money.
“The easier it is for them to secure a sustainable supply of stable and reproducible proteins, the more medical innovations we’ll be seeing coming from our shores.”
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