Regents Professor creates vaccines for developing countries
Regents Professor creates vaccines for developing countries
February 13, 2004
Skip Derra
ASU News Releases
Charlie Arntzen has been exploring the use of crops to produce vaccines for 13 years. While his team's research has made some notable advances, the work has not captured the commercial attention of the pharmaceutical industry, which has the clout and resources to bring new products to market.
"There is a major market failure in trying to convince big pharma to play a role in producing new vaccines against many infectious diseases," Arntzen says. "They are concerned with working in high value markets, like cancer vaccines or Alzheimer's vaccines. But dengue fever? Who gets it? Primarily, the very poor, living in tropical settings without basic public health infrastructure."
In spite of the lack of commercial interest, Arntzen, a recently appointed Regents Professor and the Ely Nelson Presidential Chair in plant biology as well as the founding director of the Arizona Biodesign Institute, remains a champion of plant-derived vaccines, especially for the developing world.
Diarrheal diseases that annually kill more than 2.5 million children under the age of five include cholera , E.coli and the Norwalk virus. Plant-derived vaccines can be targeted to infectious diseases like these that disproportionately affect the poor.
"No American or European company wants to make vaccines for diarrheal diseases such as cholera," Arntzen says. "Predominantly poor people get these diseases. While there is no market incentive in the developed world, there is a market, but more importantly a need, in the developing world."
In the face of this challenge, Arntzen continues working on plant-derived vaccines, and recent advances are moving the project into some unexpected areas. For example, the researchers are now trying to make their plant-derived vaccines look like traditional pharmaceutical products.
"We are going away from the idea of simply eating fruit to get immunized and shifting into a production strategy where we take a tomato, slice it up, freeze dry it, grind it into a powder and put it into pills," Arntzen says. "Our pulverized material looks like a conventional medicine even though it comes from a food."
Researchers in Arntzen's team are harvesting tomatoes, grown in their greenhouse at ASU East, and slicing them up and removing the seeds and soft tissue. They then take what is left and put it in a freeze dryer, what basically amounts to a customized refrigerator that extracts water from cold samples. Devoid of almost all its water, the resulting product can be easily ground into a powder and put into capsules.
The key to the process is freeze-drying the material, which stabilizes the vaccine, allowing it to retain its
effectiveness without refrigeration.
Refrigeration of traditional vaccines adds significantly to their cost when they have to be delivered to remote
locations in developing countries. Because the end users of Arntzen's vaccines are poor and not easy to reach, a major goal of the project is to produce vaccines that are heat-stable and don't require refrigeration.
"What we are doing is biomimetics," Arntzen says. "We are trying to mimic nature.
"If you look at a dried seed, you are looking at nature's way of storing cellular material such as proteins. When a seed develops, it goes through a maturation stage where the plant sucks out almost all of the water. When it occurs, the sugars and other materials within the cell stabilize the internal structures," he explains.
"So we thought, if a plant does that in nature and gets viable seeds, how do we mimic that with a vaccine to protect it," Arntzen explains. "This is where we have focused on the heat stable part of the project.
We are working on the dehydration of plant tissue to mimic nature."
To date, the group has focused on two vaccines to prevent diarrhea, an oral Hepatitis B vaccine, and they are beginning projects for vaccines against Papilloma virus, plague and the Ebola virus.
Their immediate goal is to demonstrate the manufacturability of their vaccines so a company, preferably one from a developing nation that wants to immunize its population in a cost-effective way, could easily pick it up and use it.
"Our aim is to develop heat-stable, oral vaccines that can be made using basic agricultural and food-processing technologies available
in any country," Arntzen says. "We're going to try to make it so easy that
any country can produce their own
Arntzen is one of eight new Regents Professors, one of the university's highest honors for faculty members. The others include Ronald Carlson, English professor and author; Phil Christensen, Korrick Professor of Geological Sciences, Gene Glass, professor of educational leadership and policy studies; Luis Gomez-Mejia, Horace Steel Arizona Heritage Chair in management; Stephen Pyne, life sciences professor and authority on fire; Psychology Professor Irwin Sandler, director of the Center for Prevention Research; and Mary Lee Smith, educational leadership and policy studies professor.
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