New data discovered about early-stage anthrax infections

Scientists have added new detail to their picture of early-stage anthrax infection that may help efforts to create new vaccines that may block that part of the anthrax cycle.

Researchers from the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health, have identified the mechanism by which anthrax bacteria initiate anthrax infection while outnumbered and surrounded by immune system scavenger cells.

According to their research, Bacillus anthracis, to initiate an infection, releases a toxin that binds to immune cells through two receptors known as TEM8 and CMG2, which are found on the cell’s surface. The binding allows for two additional toxins to enter the cells. These toxins prevent the bacteria from being ingested or killed.

NAID researchers Stephen Leppla, Shihui Liu and their colleagues bred mice that lacked the CMG2 receptors on two kinds of immune cells. Immune cells without the CMG2 receptors were found to be completely resistant to anthrax infection. They experienced only a slight swelling at the site of attempted infection, but were able to clear the body entirely in two weeks. The control group’s normal mice all died within six days.

The scientists reached the conclusion that anthrax bacteria use the CMG2 receptors to impair the scavenging action of certain types of the body’s immune cells during infection, giving the bacteria the time it needs to multiply and overwhelm the immune system. Developing drugs that are capable of inhibiting the anthrax bacteria’s use of the CMG2 receptor may become the key in treating and preventing anthrax.

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