Study exposes key to killer bugs' invasion of the body

LONDON - Scientists have discovered how bacteria that cause infections such as anthrax, bubonic plague and typhoid avoid the body's immune system - a finding that could pave ways to control the deadly diseases.

In laboratory experiments using mouse cells, researchers at the University of California, San Diego pinpointed an enzyme called PKR that leads to the destruction of macrophages, large white blood cells that protect the body against pathogens.

"If we are able to develop specific inhibitors of PKR, and the drug industry can easily produce them, we may be able to control these nasty infections," said Michael Karin, a professor at the university.

Professor Karin and his colleagues, who reported their research in the science journal Nature, think their finding could also be useful in battling lethal strains of influenza.

"Every year, you have tens of thousands of deaths among people infected with the flu. We believe this super-lethal type of flu is not due to the virus alone, but to a bacterial super-infection that follows the viral infection."

Professor Karin and his colleagues discovered how the bacteria that cause anthrax, bubonic plague and typhoid trigger signals that lead to the self destruction of macrophages.

"Instead of the macrophage being able to swallow the bacteria and recruit other white blood cells to the battle, it kills itself," the professor said.

Mice without PKR were found to have healthy macrophages that were resistant to the pathogens and could prevent infection.

- REUTERS