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Potato hepatitis vaccine a success
By MIKE TONER
Cox News Service
ATLANTA - February 15, 2005 — Researchers reported Monday that potatoes genetically modified to carry a vaccine against hepatitis B have been successfully tested in humans.
More than 60 percent of the volunteers tested showed signs of increased immunity roughly equivalent to a standard vaccination after eating a single 4-ounce portion of raw transgenic potatoes. Two helpings of bite-sized potato bits produced even higher immunity levels.
University of Arizona biologist Charles Arntzen said the findings provide "compelling evidence" that plant-derived hepatitis B vaccines could help combat a disease that infects 115 million people worldwide and kills more than 1 million a year.
There are already two conventional vaccines for hepatitis B, but high costs and distribution problems keep them from reaching more than half the people in underdeveloped countries who would benefit from them. In the United States, all newborn children are supposed to be routinely vaccinated for hepatitis B, a serious viral disease of the liver that can cause liver cancer, liver failure and death.
Arntzen's goal is not to find a way to slip vaccines into everyone's french fries. Cooking, in fact, would destroy the active ingredient. Instead, he wants to use the potatoes to "grow" vaccines that could be ground up, freeze-dried, incorporated in capsules and easily dispensed as an oral vaccine.
"We don't want people thinking that vaccines are going to start showing up on the supermarket shelf," Arntzen said. "These plant-based vaccines would be grown in greenhouses under controlled conditions, and the products would be regulated as strictly as any other drug."
The latest results, reported in the current issue ofProceedings of the National Academy of Sciences, do, however, underscore some of the dramatic advances in the fledgling field of "bio-pharming" — the use of genetically modified crops as vehicles for the production of drugs, vaccines and industrial chemicals.
Arntzen has previously modified potatoes to produce small batches of vaccine for Norwalk virus, which is frequently blamed for outbreaks of food-borne illness on cruise ships and for travelers' diarrhea. He says that initial human trials of that vaccine have also successfully induced immunity.
Other researchers have tinkered with the genetic makeup of tomatoes, tobacco, corn and other crops to produce promising compounds for the treatment of cystic fibrosis and non-Hodgkins lymphoma, as well as plant-based growth hormones, contraceptives and blood thinners.
Environmental and food safety groups have been sharply critical of federal and state efforts to regulate such developments. Arntzen himself worries that the absence of any regulatory authority for plant-based pharmaceuticals could delay commercialization of his vaccines.
Unlike Arntzen's potatoes, which were grown in greenhouses in Ithaca, N.Y., many experimental transgenic crops are grown in open fields, where there is a greater risk of contaminating food crops during planting, harvesting or processing.
In once recent case, Texas-based ProdiGene failed to eliminate bio-pharm corn plants from a soybean crop planted in the same field. The company was fined $250,000 and required to pay $3 million for expenses related to destruction of 500,000 bushels of potentially contaminated soybeans.
Only last week, a federal court in Hawaii ordered the U.S. Department of Agriculture to disclose the location of previously secret open-air tests of all bio-pharm crops being grown in that state.
"No one wants to accidentally get contraceptives in their cornflakes," says Paul Achitoff, an attorney for Earthjustice, representing several environmental and food groups. "Given the potentially disastrous effects these experiments could have on human health and the environment, we hope this ruling will result in lifting the veil of secrecy."
Mike Toner writes for The Atlanta Journal-Constitution. E-mail: mtoner@ajc.com
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