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Tobacco plants may produce anthrax vaccine

ORLANDO - A University of Central Florida professor has developed an anthrax vaccine made from genetically engineered tobacco plants - an acre of which could produce enough medicine for the entire country, he said.

Henry Daniell's research, published in this month's edition of the Infection and Immunity Journal, showed that mice injected with his vaccine and subjected to high levels of anthrax toxin by National Institutes of Health researchers were able to withstand infection.

The tobacco was modified by injecting its chloroplast with the same protective antigen ordinarily grown along with the disease in expensive research fermenters - a process that can sometimes taint the antigen.

"As the plants grow, we are able to make that cell into a whole plant. From one cell, every single cell of the new plant will contain 10,000 copies of this foreign gene," Daniell said.

Daniell said he chose tobacco because it is a perennial crop, can be harvested several times a year and eliminated the potential for harming consumer foods.

He said a single acre of tobacco could produce 360-million anthrax vaccine doses a year - far more than current facilities can handle.

However, before the vaccine can be mass-produced and stockpiled, it must pass clinical trials in which humans are injected with the vaccine, but not anthrax, to test immunity levels.

To get the antigen, tobacco leaves are harvested and squeezed, and the good protein is separated from thousands of others in a process that can achieve 99.9 percent purity, Daniell said.

Daniell's research, which began about 3 years ago, was sponsored by a $1-million NIH grant and $2-million from the U.S. Department of Agriculture.

He said it's much less expensive than producing the vaccine in fermenters, which can cost hundreds of millions of dollars in upfront investment.

Emergent BioSolutions Inc., with facilities in Frederick, Md., and Lansing, Mich., is now the nation's only maker of a licensed anthrax vaccine. Like the UCF-produced vaccine, its product requires six shots over several months.

However, a company called VaxGen Inc. has signed an $877.5-million contract to produce 75-million doses of a next-generation vaccine to add to the nation's emergency stockpile. It is expected to require no more than three doses, but is pending final approval.

[Last modified December 21, 2005, 00:51:17]