After all the poor health outcomes caused by tobacco over centuries, it’s about time the plant started doing something good. Scientists in the United Kingdom have developed a technique to infect relatives of the tobacco plant with a virus containing the genetic material of polio. Why? To produce leaves from which a polio vaccine can be extracted. The procedure is reportedly affordable, straightforward, and efficient, and may be utilized to create treatments for newer threats such as Zika and Ebola.
The team of scientists at John Innes Centre in Norfolk essentially sought to turn the tobacco plants into vaccine “factories.” The vaccines produced by the altered tobacco plants are called a virus-like particle, which is an empty shell that possesses an exterior identical to the potent polio virus but does not contain the features that could cause infection in humans. To harness the tobacco plants into disease-fighting action, the team wrote new genetic instructions, fused with viruses that naturally infect tobacco plants, that were mixed into soil and absorbed by the plants. Upon infection, the tobacco began producing the virus-like particles, which were extracted through a process that involved blending infected leaves with water.
In animal experiments, the tobacco-produced vaccines proved effective and 3D imaging analysis demonstrated that the particles appear identical to the polio virus. The plant-based vaccines also have an advantage over traditional polio vaccines, whose production carries the risk of infection with actual polio. “Current vaccines for polio are produced from large amounts of live virus, which carries a threat of accidental escape and re-introduction,” said Dr. Andrew Macadam, principal scientist at the UK’s National Institute for Biological Standards and Control. “This study takes us a step closer to replacing current polio vaccines, providing us with a cheap and viable option for making virus-like particle-based vaccines.”
Still, plant-produced vaccines have a ways to go before they are ready for wide distribution. “The initial results look impressive,” said Denis Murphy, professor of biotechnology at the University of South Wales. “However, there are very few plant-based vaccine manufacturers and almost no licensed human vaccines that are currently produced in plants. This is an important achievement. The challenge is now to optimize the plant expression system and to move towards clinical trials of the new vaccine.”