University of Florida researchers have revealed how the inhaled form of anthrax paralyzes the body's defenses and prevents immune cells from reaching the site of infection.

Anthrax killed five people in 2001 when letters containing the bacteria's spores were sent through the mail. The UF findings, published last week in the EMBO Journal, may lead to quicker diagnoses for anthrax victims.

The disease causes flu-like symptoms that can take weeks to develop, according to the Centers for Disease Control and Prevention. But once the first symptom appears, the disease progresses rapidly and patients often die from shock before they realize they have more than a common cold. The current method of detecting anthrax relies on lab cultures that can take days to complete.

"We're looking for approaches to detect anthrax earlier in the blood," said Russell During, Ph.D., a postdoctoral fellow at UF's College of Medicine. "We're trying to develop a test that would allow detection within two or three hours of the bugs entering the blood and secreting toxins."

Once inhaled, anthrax releases a lethal toxin that immobilizes the white blood cells that normally seek and destroy invading bacteria. Just traces of the toxin can slow movement of these cells, called neutrophils, by 50 percent, UF researchers discovered.

"Neutrophils have to get to the infection to kill anything. If you paralyze them so they don't move, they can't protect you," said Fred Southwick, M.D., division chief of infectious diseases at the UF College of Medicine and the study's lead author.

But exactly how the anthrax toxin wards off neutrophils has puzzled scientists for years. Immune cells rely on rod-shaped filaments called actin to propel them toward an infection. In a previous study, Southwick found that the toxin prevents actin assembly, leaving neutrophils stuck in the mud.

"Actin is important because it's the motor that causes neutrophi
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Contact: Ann Griswold
anngriswold@gmail.com
352-273-5810
University of Florida
5-May-2007