Growing Vaccinated Fruits and Vegetables

ByLee Dye

Oct. 11, 2000 -- Charles Arntzen wants to save the lives of millions of children threatened by deadly infectious diseases, and he wants to do it by feeding them a slice of a banana.

“We know what the problem is,” he says as he leans back in a chair on a courtyard at Arizona State University in Tempe. “We have 15 million kids dying every year in Third World countries from infectious diseases that could be prevented.

“And we know what the solution is,” he adds. It is to inoculate those children with vaccines that can fight off diseases such as hepatitis B, cholera, and various deadly types of diarrhea.

Inoculations Problematic

Although major progress has been made in inoculating children in much of the world, in the poorest of the poor nations, little has been achieved. That leaves about 20 percent of the world’s infants vulnerable to horrible diseases, according to the World Health Organization.

Inoculating these impoverished children is almost impossible with the current technology, Arntzen says. Vaccines that are now available have to be injected, with the single exception of the oral polio vaccine. And injections are too expensive and too problematical in much of the world.

“Vaccines need to be refrigerated from the point of manufacture to the point of use,” Arntzen says. “They usually need skilled medical delivery people because they are delivered by needles, and needles are potentially hazardous.” Contaminated needles may do more to spread disease than contain it.

Although philanthropic organizations pick up most of the cost, hundreds of millions of children are left unprotected because an inoculation that may cost pennies to produce is simply out of their reach.

What to do about all of that has consumed Arntzen ever since a 1990 conference in New York City, sponsored by the WHO. The Children’s Vaccine Initiative came out of that meeting, and it changed the life of Arntzen, then a plant biologist at Texas A&M University.

First Potatoes, Tomatoes

Arntzen figured some plants could be genetically modified to produce the proteins that would jump-start the human immune system so it could destroy disease-causing pathogens before they could do their damage. A hepatitis B gene, for example, added to a plant could cause the plant to produce proteins that would be consumed like any other food, and stimulate the immune system to fight hepatitis B. In other words, an edible vaccine.

A short time after the New York conference, while visiting Bangkok, Arntzen watched a young mother soothe a crying baby by feeding the infant a slice of a banana. It struck him then that bananas were the junk food of the Third World, so easily grown that many children eat them as treats.

Wouldn’t it be fantastic, he thought, if a crop that loves to grow in countries that desperately need inoculations could be engineered to produce the vaccine? That would provide a local source that could be grown, harvested and processed in the country where it would be used.

Arntzen set out to do just that, a journey that would take him to Cornell University as president of the Boyce Thompson Institute for Plant Research, and now to ASU, where he wants to move the research he pioneered over the past decade from the lab to the outside world.

He didn’t start out with bananas, one of the most difficult of all plants to genetically engineer. He began with tobacco, one of the simplest, just to prove out the principle. He had enough success to conclude that he was on the right track.

He moved on to potatoes, and tomatoes, and before leaving Cornell completed very limited clinical trials showing that the desired immune response was produced in both mice and humans. There were no serious side effects, but the subjects had to eat a lot of potatoes, and they had to eat them raw. Cooking the potatoes would break down the proteins that provoke the immune response.

Somehow, the vaccine production has to be beefed up so that no one has to eat a bag of raw potatoes to get inoculated, but researchers believe that’s only a matter of time. Arntzen sees the day when children will be given a medical version of an Oreo cookie, except the white stuff in the middle will be a slice of banana ready to do its part to save the youngster’s life.

Many Steps to Banana Cure

There are, of course, enormous hurdles to overcome before that can happen. Arntzen says any vaccine would have to be approved in this country before it could be tried oversees to avoid the appearance of using poor children as research subjects. That will involve costly and time-consuming clinical trials.

And there is the problem of maintaining quality. William H. R. Langridge of Loma Linda University has stressed that it will be important to ensure that plants produce the vaccines in the right concentrations so that the dosage is consistent and correct. Langridge is working on an edible vaccine for cholera.

Too much vaccine would have just the opposite of the desired effect, creating tolerance of the disease instead of provoking an immune response, Arntzen says.

That means crops used to produce vaccines would have to be isolated from other crops and kept out the food chain. That could be done, Arntzen suggests, by making them sterile and unable to reproduce, and perhaps a lot less tasty than food crops.

The beauty of the concept, however, lies in the fact that vaccines could be homegrown in crops around the world, involving local agencies and companies.

“I’d like to ship seedlings” all over the world, where they could be grown and harvested as part of a local pharmaceutical operation, Arntzen says.

No Economic Push

The last thing he wants to see is all of this just chalked up to more research.

“I don’t want this to end up as a standard academic lab that publishes a few papers and the dies,” Arntzen says. He and others fear that if they don’t do it, nobody will.

For pharmaceutical companies, there’s more money to be found in reducing male baldness than in producing vaccines, he adds.

“I know no pharmaceutical company is going to do it because there’s no driving economic reason for them to do it,” Arntzen says. “So I’m going to spend the next five years trying to make it so easy that anybody can do it.”

If he succeeds, much of the world will see more of their infants live past childhood.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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