The bacterium that causes tuberculosis uses a surprisingly underhanded trick to invade cells, researchers at Washington University School of Medicine in St. Louis announced today. The strategy is clever and effective - and it may one day prove to be the disease's downfall. Although such a vaccine could be developed only after many more years of study, researchers are excited about the new insight into the common and deadly microbe. Brown is a professor of medicine and of cell biology and physiology at the School of Medicine.
Tuberculosis is a growing global menace that kills more people than any other infectious disease.
Three million people die from it each year, and as many as one-third of the world's population is infected with Mycobacterium tuberculosis , the bacterium that causes the disease. Researchers have long known that M. tuberculosis makes its living by preying on macrophages, the immune system warriors that usually consume bacteria. The bacterium enters a macrophage and apparently multiplies until the cell ruptures, releasing more bacteria to attack other macrophages. Schorey, Brown and colleagues conducted test-tube studies with M. tuberculosis and a few of its close relatives including M. leprae , which causes leprosy, and M. avium , which frequently infects AIDS patients. The researchers found that all three bacteria share a special trick for finding and invading cells.