Professors hope vaccines from tobacco will help fend off plague
Government fears disease could be used as bioterrorism weapon
While the plague may not seem to pose a threat to the general public, ASU is helping the Department of Defense create a vaccine to fend off what could be a bioterrorism weapon.
Biodesign Institute Professors Hugh Mason, Luca Santi and Charles Arntzen are developing a vaccine that will protect soldiers from a potential plague attack.
Once feared as the disease that caused the Black Death epidemic in the Middle Ages, plague is usually marked by symptoms of fever, weakness, pneumonia and bloody saliva. In the case of bubonic plague, symptoms also include swollen lymph glands, called buboes.
"Terrorists could disseminate it [plague] in an aerosolized bacterial cloud," Mason said. "When you breathe it in, the disease develops faster and develops pneumonia."
Funded by the Defense Department, Mason, Santi and Arntzen's plague vaccine could be used by the Army if commercialized.
By harnessing the power of a plant virus called TMV, or tobacco mosaic virus, which is injected into tobacco leaves, this plague vaccine can be reproduced more efficiently than previously developed vaccines.
"There are several good reasons for using tobacco," Santi said. "It's a non-food, non-feed crop. That keeps it out of any food channels.
"It's also easy to grow, easy to manipulate, and there are lots of varieties."
The vaccine should also prove more effective than other plague vaccines that cause side effects like severe inflammation and sometimes shock, Mason said.
Plague, a disease caused by the bacterium Yersinia pestis, has been used as a weapon before.
In the Middle Ages, people would catapult plague victims' bodies into a city to generate an epidemic, Mason said.
During World War II, Japan also used plague as a weapon against China, when they dropped infected fleas in air raids.
Plague now affects an average of five to 15 people in the western U.S. each year, the Centers for Disease Control reported.
Animals typically found in western states, like bobcats, squirrels, rats and prairie dogs, are common carriers of the disease.
Worldwide, an estimated 1,000 to 3,000 cases occur annually, reported the World Health Organization.
While these cases can be treated with antibiotics, scientists are concerned that certain plague strains can become resistant to those antibiotics.
The research team addressed this issue by including two important proteins, called F1 and V, in their vaccine.
Fused together through recombinant DNA techniques, these proteins stimulate an immune response that builds antibodies and protects against plague infection.
Lance Batchelor, a senior biochemistry and cellular biology major, worked with the Biodesign research team, cloning the F1 and V proteins and splicing DNA together.
"If you put two different proteins together, it's almost impossible for the strain to make the mutations necessary to resist the vaccine," Batchelor said.
The team tested the vaccine on eight guinea pigs. Although two of the guinea pigs eventually died, all produced the necessary antibodies, Mason said.
Before it can be distributed for human use, Mason said he wants to improve the stability of the vaccine and modify the production method, so that mass amounts of vaccine can be supplied.
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