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How Anthrax Kills!

© Neal Rolfe Chamberlain

In March 1998 two men claimed they had the anthrax bacteria and might release it in the United States. As it turned out the men only had the form of the bacteria used to vaccinate people to prevent them from getting anthrax. Recent events this fall (2001) have resulted in at least 22 confirmed cases of anthrax and 4 fatalities (Nov. 2, 2001). Unknown people are sending anthrax spores in the mail to media people and politicians for reasons we have yet to learn.

Anthrax is a bacterial infection that if inhaled can cause a deadly infection. The bacteria that causes anthrax is called Bacillus anthracis. For more information on the diseases this bacterium causes go to Anthrax: To Fear or Not To Fear.

Bacillus anthracis produces three different proteins that cause most, if not all, the damage in a person with anthrax. These proteins are called protective antigen, edema factor, and lethal factor. Lethal factor is the protein that causes people to die. Edema factor causes you to swell up and also causes a lot of fluid to accumulate in the lungs. Protective antigen helps lethal factor and edema factor get into our cells and once those two villains are in our cells protective antigen then binds to lethal factor and edema factor to help them act on damaging our cells.

Edema factor increases the amount of adenylate cyclase in a cell. When this happens the cells of our body lose water and the water goes in between our cells causing the swelling to occur. Unfortunately, how lethal factor kills cells had not been determined until very recently. The May 1, 1998, issue of Science contains an article by Duesbery et. al. titled "Proteolytic Inactivation of MAP-Kinase-Kinase by Anthrax Lethal Factor."

Now don't tune out just yet. The title simply means that lethal factor is able to cut into pieces a protein called mitogen-activated protein kinase. Mitogen-activated protein kinase is important in helping cells divide and in causing cells to differentiate (go from a cell that does not have a specific job to one that does). By destroying mitogen-activated protein kinase the cells do not divide or differentiate and instead they die.

Antibiotics kill Bacillus anthracis, but, by the time the bacteria are killed off by the antibiotic, it is usually too late and the person dies. That is because too much lethal toxin has been made and is already destroying the patient's cells in vast numbers. Now that we know how the lethal factor kills cells and that it does so by cutting

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