Using blood samples from volunteers, the researchers studied how neutrophils reacted when exposed to a purified form of anthrax lethal toxin, the part of the spore linked to the illness.
Unlike an intact inhalation anthrax spore, the pure toxin is not dangerous for researchers to use and allows them to isolate specifically how the toxin is affecting cells, Southwick said.
Low doses of the lethal toxin stopped the protein actin from building filaments to steer the neutrophils, stopping the body's immune response, the study found.
"Neutrophils crawl around in the body and roll around in the bloodvessels and whenever they sense bacteria, they gobble it up likePac-Man," said Russell During, a graduate student in the Interdisciplinary Program in Biomedical Sciences who worked withSouthwick on the study. "If neutrophils are the first responders and they never get there, you're fighting a losing battle."
And inhalation anthrax works fast, which is one of the reasons why it is usually fatal, according to the CDC. The disease can be treated with antibiotics, but people often don't seek treatment until it is too late,said Philip C. Hanna, an associate professor of microbiology and immunology at the University of Michigan Medical School.
"A person can die before they know they are terribly sick at all," Hanna said.
Symptoms of inhalation anthrax resemble the common cold and progress to breathing problems, shock and often death, according to the CDC.
But in the 2001 attacks, only half the 10 people who contracted inhalation anthrax died. The five other victims were diagnosed and treated earlier due to quick communication from the doctors who pinpointed the first anthrax infection, Southwick said.
Twelve other people contracted cutaneous (skin) anthrax infections, which are not usually fatal.
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Source:University of Florida