Test vaccine attacks anthrax’s cause, effect

ASSOCIATED PRESS

A new vaccine that launches a two-pronged attack on anthrax — battling both the bacterium that causes the disease and the toxin it produces — is undergoing preliminary tests.

The dual-acting vaccine goes a step beyond the current product that only targets the deadly toxin, according to researchers at Harvard Medical School, who tested it in mice.

Their findings are being published this week in the online edition of Proceedings of the National Academy of Science.

Interest in anthrax was spurred two years ago when spores of the disease were mailed to news media and lawmakers. Five persons died and the U.S. Postal Service had to shut down major facilities for decontamination. The agency continues to irradiate mail addressed to federal offices to prevent another such attack.

In another sign of progress, researchers say they now know how to diagnose anthrax quickly and efficiently, an advance that could help doctors better deal with a large-scale attack.

In a separate study, scientists report fever and cough are common in both anthrax victims and flu sufferers. But people sickened by anthrax are also likely to suffer from mental confusion, dizziness, shortness of breath, nausea and vomiting. Runny noses and sore throats are much more common in people with the flu. The study appears in today’s Annals of Internal Medicine.

Bacillus anthracis, the bacterium that causes anthrax, protects itself in the human body with a coating of molecules that prevents the immune system from detecting it. It can then multiply and produce its deadly toxin.

Current vaccines sensitize the body to that toxin so the immune system can fight it. But the newly developed version also sensitizes the immune system to the coating that protects the bacteria, so it can attack the bacteria.

“Clearly, there is a need for a better anthrax vaccine,” said Julia Y. Wang, an assistant professor of medicine who was part of the team. “The bivalent vaccine we came up with is likely to be much more effective at protecting against systemic anthrax because it targets both virulence factors of Bacillus anthracis — its toxin and its capsule.”

In the Harvard test, mice immunized with the new vaccine then injected with anthrax toxin survived, while nonimmunized mice similarly injected died within hours.

The researchers didn’t have access to anthrax bacteria, however, so they used a substitute to test the vaccine’s effectiveness.

Blood from the immunized mice was tested with Bacillus licheniformis, which coats itself with a protective cover similar to that used by Bacillus anthracis. In lab tests, blood from immunized mice coated and killed bacillus licheniformis.

Dr. Wang said in a telephone interview that testing are planned of the ability of the vaccine to protect mice from the anthrax bacterium itself.

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