Vaccines grown in plants show promise

Posted on 17 Aug 2017 by Michael Cruickshank

A team of scientists has seen success growing vaccines in plants which have been 'hijacked' to produce new compounds.

Plants closely related to tobacco were used to grow polio vaccines. Image courtesy of Leaf Expression Systems.
Plants closely related to tobacco were used to grow polio vaccines. Image courtesy of Leaf Expression Systems.

Researchers working at the John Innes Centre in Norfolk in the UK, as well as Oxford University, used a plant closely related to tobacco in order to grow vaccines to the polio virus.

To achieve this, they first took a polio virus then genetically modified it so it could infect plants. This virus was then implanted into soil bacteria which spread the virus to the tobacco plants being used by the researchers.

Once the virus had infected the plants, they began producing virus-like particles which could be harvested from their leaves.

Critically, these virus-like particles were almost exactly the same as the traditional polio virus, however, they would cause no ill effects in humans.

While they could not make a person sick, due to the fact that they mimicked the shape of the virus particle, they would still create an immune response in the human body, something which would lead to immunity.

In order to prove that these particles could indeed induce this effect, while still causing no harm, the researchers enlisted the help of an advanced cryo-electron microscope at Diamond Light Source’s Electron Bio-Imaging Centre (eBIC).

“By using Diamond’s visualisation capabilities […] we were able to visualise something a billion times smaller than a pinhead. Through information gained at Diamond, we also verified that these have essentially the same structure as the native virus to ensure an appropriate immune response,” said Dave Stuart, director of life sciences at Diamond and professor of structural biology at the University of Oxford.

The next step for the team will be clinical trials, which will hopefully show that their technology is indeed safe in humans. Should they be successful, the same approach could be used to develop vaccines for a wide range of viruses.

Cheaper and faster vaccines

While the team has yet to fully prove the viability of plant-based vaccines, the approach has great potential to cheaply and quickly produce vaccines.

Currently, many vaccines are produced within chicken eggs, something which is both expensive and has a turnaround of months.

By growing viruses in plants instead, the researchers could make it possible for a vaccine to be made from a novel virus in a month, something which could save many lives in the event of a flu pandemic.