Taking the kids to the doctor can be a battle, especially when they need a shot. But soon children and adults alike could receive vaccines from corn puffs or a jar of baby food.Edible vaccines grown in corn, bananas or tomatoes could not only make vaccination more convenient in wealthier countries but help global immunization efforts (see “Making Needles Needless,” TR September/October 1998). Barriers to immunization in poor countries include the cost of vaccines and needles, lack of health-care workers and difficulty in refrigerating the doses. Hepatitis B vaccine, which costs 50 cents for each dose, remains out of reach for many of the world’s poor; over 900,000 people die each year from hepatitis B. Producing the vaccine in plants could reduce the cost to less than a penny per dose. And simple food processing like drying and grinding could create nonperishable preparations.
ProdiGene, based in College Station, TX, is working to bring edible vaccines to the marketplace. ProdiGene creates its vaccines by genetically engineering corn to produce bacterial or viral proteins that elicit immune responses when eaten. Last year, the company received a patent covering any viral vaccine produced in any plant. ProdiGene has also filed patents on edible bacterial vaccines, says chief scientific officer John Howard. The company plans to test an E. coli vaccine in humans this year and hopes to do the same for a hepatitis B vaccine early next year.
Lead inventor on the patent is Charles Arntzen, a plant molecular biologist who originated the idea of plant-grown vaccines a decade ago at Texas A&M University. Arntzen, now at Arizona State University, is not affiliated with ProdiGene; the company bought rights to the technology from Texas A&M. Arntzen says the ProdiGene work is interesting, but points out there are other tacks. “Since there is a potential for at least a hundred different vaccines for different viruses, I would expect that there’s not going to be any single technology approach. It’s really going to be disease specific; it’s going to be specific for the population that you’re trying to immunize,” Arntzen says.
Indeed, three separate patents covering edible vaccines issued in 1997 to Washington University in St. Louis are now licensed to Dow AgroSciences. But David Wheat, an analyst at the Boston-based Bowditch Group, says ProdiGene is in a good position. “ProdiGene is reputed to have made sure to have good, tight access to all of the intellectual property they need. They will be able to practice this technology without roadblocks from other companies,” he says.
While a number of academic groups are developing edible vaccines for humans, ProdiGene is the only company pushing ahead with human clinical trials. “We believe that the opportunities are tremendous,” says Howard. “We also know there’s other people looking at it, and what we’d like to do is work with all those other people. We would like to see above all the technology go forward.”