Possible asthma vaccine in a few years, through GM?

Allergy Vaccine
Thursday, 13 November 2003




An Australian microbiologist may have found a new way to vaccinate against asthma, and there?ll be no needles, just open wide, and swallow. Dr Simon Hogan from the ANU in Canberra is part of the brave new world of genetically modified plants being designed not for food, but as plants that can deliver a vaccine.

His remarkable finding in experiments with asthematic mice is that it?s possible to introduce an allergen to their stomach, which creates an immune reaction, activating cells against the allergen. When their lungs were exposed to the same allergen, the previous immune response cells in the stomach rush to the lungs via the bloodsteam protecting the mice from sensitisation, thus preventing asthma.

One day these plants could provide a cheap, sustainable and easily accessible vaccination not only for asthma is Australia but also for many of the diseases that plague the developing world. But there is still a major obstacle, this vaccine uses GMO?s to deliver it?s punch, and public acceptance of the technology is a long way (full transcript...)


Full Program Transcript:
Narration:
Asthma: It?s one of Australia?s major health problems. To date it can?t be cured, nor can it be prevented.
Now the race is on to find the holy grail of medicine ? a vaccine for asthma.
These scientists are taking a controversial new approach; they?re trying to create a vaccine using genetically modified plants.

Simon:
from the definitive moment where we showed that GMO technology does have the ability to suppress allergic disease, we knew this has great potential

Narration:
It all started when these two men met to investigate a completely different problem.
TJ Higgins, head of Plant Sciences at CSIRO, had created a genetically modified lupin plant for animal feed. He?d added a sunflower seed protein to increase the feed value.
He approached microbiologist Simon Hogan to investigate the safety issues surrounding the newly created plant.

TJ HIggins:
We got together when I got to the stage of testing our transgenic lupins for safety. I was particularly interested in whether or not this new protein that we'd added into lupins would be a possible allergen.

Narration:
Simon took the genetically modified lupin back to the lab. He wanted to see if it was causing an allergic reaction in mice.

Paul:
So you?ve got your GM feed, with the added allergen, what?s the next step.

Simon:
Well once we got our genetically modified lupin and our normal lupin we fed it to the mice for a period of time

Narration:
These mice are specially sensitised to the sunflower seed allergen, so if they breathe it in they will get asthma.
Half were fed genetically modified lupin and half were fed normal lupin ? then Simon tried to induce asthma in the mice.

Simon:
So we put the mice in a chamber - you can see we form a mist containing the purified allergen, and then we connect this to the chamber

Paul:
So this is like exposing a normal asthmatic to the things that really trigger their problems

Simon:
Correct yes.

Narration:
When Simon compared the lung function of the two groups, he found eating the allergen caused something totally unexpected.

Simon:
I found some quite interesting data suggesting that it may be able to in fact, not induce allergic responses, but suppress an allergic response

Narration:
It seemed counter-intuitive. It appeared that the mice that had eaten the allergen that usually causes asthma, were actually protected against asthma.
Simon decided to take a closer look.
These are slices through the lungs; this mouse was not fed the genetically modified lupin.

Simon:
You can see that the airway is all blocked up//which then leads to the airway constriction and the wheezing

Narration:
This mouse had asthma.
But the lungs of the mice that did eat the GM lupin showed a totally different result.

Simon:
you can see that the airways remain open and intact and also the airway sacs remain open, and that the allows the animal to breathe normally,

Narration:
Simon realised he?d hit upon something with huge potential ? a possible way to vaccinate against asthma.

Simon:
this is the first demonstration of it?s type, and we?re very excited by it.

Narration:
The team had demonstrated something quite incredible; it?s a theory called Oral Tolerance.
If you eat enough of whatever allergen gives you asthma; and usually it?s a protein in cat hair, dust mite faeces, or pollen; you?ll actually be vaccinated against an asthmatic reaction to that allergen.
Oral Tolerance was first described at the turn of the 20th Century by HG Wells, the author of War of the Worlds.
It?s all about educating your immune system through your stomach.

Simon:
What we think can happen is that if you eat the allergen that induces a type of immune response in the stomach, a suppressive type immune response. The gut naturally develops protective responses because of the foods we eat.

Narration:
Then, if the same allergy-inducing protein is breathed into the lungs, the already trained immune cells from the gut, move through the body into the lungs. There they switch off an inflammation response, stopping an asthma attack.

Oral tolerance is a great theory, but there?s always been a problem putting it into practice ?
Pat Holt is an asthma expert from the Telethon Institute for Child Health Research.

Pat Holt:
The big problem with that is that the levels of protein that are required to be fed to people to cause them to develop immunological tolerance are reasonably high. And the proteins that are responsible for causing these allergic reactions are present in very very trace amounts in a natural environment. So it's just a matter of availability.

Narration:
In other words people even if people wanted to eat dust mites it would be impossible to eat enough of them to protect against asthma.
This is where Genetic Engineering could come to the rescue.
It might be possible to create a plant that concentrates an allergen into high enough doses to make oral tolerance a reality.
This is the CSIRO labs where genetically modified plants are created.

TJ:
So this is where we put the new gene in lupins, we use bacteria as a taxi, as a way of transferring it, into the plant.
The concept is to isolate the gene that codes for a protein responsible for asthma, such as the dustmite allergen, and to introduce this gene into a plant.

Simon:
We can design essentially a bio-reactor, a genetically modified plant that acts as a bio-reactor to produce large quantities of that allergen, and to produce large quantities quite cheaply.

Narration:
So Gm technology could finally make oral tolerance a viable way to treat allergic diseases.
Does this mean that, if the environmental and health concerns over GM plants are overcome, that one day we will be tucking into a vaccine salad?

Simon:
No we wouldn't envisage that at all, we would envisage that the genetically modified plants be used as bioreactors to produce large quantities of allergen, the allergen would be then purified and you would take the allergen as any other pill,

Narration:
Don't think you'll be popping your dust mite pills just yet, this is still just a proof of concept. But now the race for the asthma vaccine is on.