Answers on Anthrax

In the wake of recent bioterrorist releases of anthrax bacteria, some of the most critical questions raised are: What strain of anthrax was released? How can we treat it? and How can we vaccinate against it? Two NIGMS grantees are helping to answer those questions.

Dr. Paul Keim of Northern Arizona University developed the technique that authorities are using to identify the strain of anthrax used in each attack. The identity of the strains suggests whether different attacks were carried out by the same person or group and reveals clues about the source of the bacteria. Using Dr. Keim's technique, investigators concluded that identical strains of anthrax were mailed to Senate Majority Leader Thomas A. Daschle (D-S. D.), NBC News anchor Tom Brokaw, and American Media Inc. in South Florida.

Anthrax colonies isolated from the 1993 Aum Shinrikyo bioterrorist attack in Kameido, Japan.

Dr. Keim studies the evolutionary relationships among anthrax strains so that he can determine where any strain originated, even if it is subtly different from its ancestor. His technique relies on slight genetic differences between the hundreds of known strains of anthrax. His team detects these differences using a type of "DNA fingerprinting" technique related to that used in criminal and paternity cases. He has collected a library of about 1,350 different anthrax samples, and he has fingerprinted more than 900 of them.

In 2001, Dr. Keim used the technique to analyze the strain of anthrax released in 1993 by the Japanese cult Aum Shinrikyo.¹ His work showed that the attack failed because the cult members used a veterinary vaccine strain of anthrax that is not dangerous to humans.

Dr. George Whitesides of Harvard University designed a molecule that might lead to a new treatment for anthrax infection. The molecule neutralizes the bacteria's deadly effects by interfering, at a molecular level, with the assembly of anthrax's toxic machinery. It prevented illness in rats exposed to 10 times the lethal dose of anthrax proteins, showing promise as the basis of a future treatment. Dr. Whitesides and his coworkers combined two separate techniques to generate their synthetic molecule. The success of their unique approach suggests it might be widely applicable to the design other useful molecules, such as anticancer drugs or laboratory reagents.

REFERENCE

¹Keim P, Smith KL, Keys C, Takahashi H, Kurata T, Kaufmann A. Molecular investigation of the Aum Shinrikyo anthrax release in Kameido, Japan. J. Clin. Microbiol. 2001 Dec;39(12):4566-7.

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