Researchers Test "Killer" Enzyme as Anthrax Treatment

By Gerry J. Gilmore
American Forces Press Service

WASHINGTON, Jan. 29, 2003 -- An anthrax-killing enzyme now being tested by the Defense Department may one day be used as a medical treatment against the deadly bacteria, a DoD researcher said.

The enzyme, lysin, "is like a 'smart bomb' that kills anthrax, but doesn't kill anything else," noted Dr. John Carney, a pharmacologist with the Defense Advanced Research Projects Agency in Arlington, Va. "This could be an unique treatment (against anthrax) that wouldn't cause side effects."

Carney has worked three years with DARPA-contracted research microbiologists at Rockefeller University in New York, in developing more effective medical therapy for anthrax.

Lysin attacks anthrax by dissolving a hole in the bacteria from the inside out, Carney explained. Water surrounding the ruptured anthrax cell rushes in, he continued, causing it to burst.

Persons can receive vaccinations for protection against anthrax, Carney pointed out, while Cipro, doxycycline, penicillin and other antibiotics are used as treatment for unvaccinated people who've been, or may have been, exposed to the bacteria. Yet, some persons might be allergic to the antibiotics used to battle anthrax, he acknowledged.

In addition, he said, broad-spectrum antibiotics are indiscriminate. They kill all bacteria, even beneficial ones, and that can cause side effects such as diarrhea. He said the new enzyme, on the other hand, has the potential for fewer side effects because it would kill only anthrax bacteria,

Carney noted he and his associates have great hopes for the experimental enzyme therapy. Human testing, he said, is on the horizon.

"It's getting close," he emphasized, "It's been proven in rodent studies that it works." The clinical studies, Carney pointed out, are reviewed by the Food and Drug Administration, which would provide final approval for any new anthrax treatment procedure.

Anthrax makes a deadly biological weapon of mass destruction, Carney noted. After a person is exposed to anthrax bacteria, "it grows in your body," he pointed out, and releases several toxic proteins -- poisons.

Those poisons travel through the victim's blood stream and attack and destroy the body's immune system, Carney explained, hampering the body's ability to resist infections.

Untreated anthrax victims develop "an abnormal pneumonia," Carney pointed out -- the first clinical sign of the bacteria's presence. As the poisons spread, they "weaken your body and, ultimately, your organs fail and you die," he noted.

Cattle can contract anthrax, Carney explained, because "it's found in the dirt." Sheep farmers, he added, have contracted anthrax by breathing in spores coming off infected animals' wool.

Carney ticked off the three forms of anthrax: gastrointestinal, cutaneous or skin, and pulmonary. Eating infected dirt causes gastro-intestinal anthrax, he explained, while cutaneous anthrax enters the body through a break or cut in the skin.

Inhaling anthrax spores, Carney pointed out, causes the pulmonary variety of the disease. Becoming a spore, he noted, is one of the things the organism does to survive.

"Cutaneous anthrax is treatable; it's not a lethal disease," Carney explained, adding that gastrointestinal anthrax "is very uncomfortable, but is rarely, if ever, lethal."

Pulmonary anthrax, however, "is a much worse disease -- and it's lethal," he concluded.

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