Global Security Newswire

WASHINGTON — A researcher from Harvard University yesterday detailed her team’s efforts to create a new and more effective anthrax vaccine that could combat both the anthrax bacterium and the toxin it creates (see GSN, Sept. 3).

During a media roundtable held yesterday at the RAND think-tank in Arlington, Va., Harvard Medical School researcher Julia Wang outlined the various factors that make anthrax such an effective biological weapon, including ease of production and storage and its extremely lethal nature. Once anthrax spores enter the body through a skin lesion, inhalation or ingestion, they develop into the bacterium Bacillus anthracis and multiply extensively, Wang said. She added that a protective capsule over the bacterium hampers the ability of the human immune system from detecting and combating the infection. The bacteria can then kill the infected person through a massive infection of the bloodstream caused by the huge number of bacteria or through tissue death caused by the toxins produced by the bacterium once it enters the lymph nodes.

The U.S. National Institute of Allergy and Infectious Diseases provided an initial research grant of $150,000 a year for two years for the project, Wang said, adding that about $2 million of basic research is still needed. She said that her team was seeking additional NIAID funding and that several private U.S. and foreign companies were also interested in aiding the research.

According to Kenneth Shine, director of the RAND Center for Domestic and International Health Security, the currently available anthrax vaccine works by preventing the toxins created by the anthrax bacterium from destroying immune cells. The human immune system is then given enough time to build up defenses against the bloodstream infection, he said. The current vaccine has come under fire, however, because of the six-shot regimen needed to administer it and because of the side effects it can produce.

“[It is] annoying as hell to young people to have these local reactions,” Shine of the side effects caused by the current vaccine.

Researchers at Harvard University Medical School, however, have worked to develop a new type of anthrax vaccine that would combat both the bacterium and the toxins it produces, Wang said. To counter anthrax toxins, the new vaccine produces antibodies that attach to one of three toxins produced by the bacterium called protective antigen, which helps the toxins penetrate a human cell. The antibodies then prevent the other two toxins produced by the bacterium — edema factor and lethal factor — from combining with the protective antigen to enter and destroy cells, she said.

In addition, Wang said, the vaccine also helps combat the protective capsule surrounding the anthrax bacterium. This enables the human immune system to better combat and destroy the infecting bacteria, she said. The new vaccine would likely only require a three-shot regimen, but the exact number of shots that would be needed is still unknown, Wang said.

In tests with mice, the vaccine has been found to have protected all inoculated subjects against the anthrax toxin, Wang said. Under the U.S. Food and Drug Administration’s “animal efficacy rule,” animal-testing data can be used to demonstrate a new treatment or vaccine’s effectiveness when it cannot ethically or feasibly be tested on humans. Harvard researchers are now working to establish collaborations with other facilities to test the new vaccine against different types of animals, Wang said, adding that they would like to test against rabbits and guinea pigs.

The U.S. National Institute of Allergy and Infectious Diseases provided an initial research grant of $150,000 a year for two years for the project, Wang said, adding that about $2 million of basic research is still needed. She said that her team was seeking additional NIAID funding and that several private U.S. and foreign companies were also interested in aiding the research.