26. Studying Tuberculosis
David Russell
David G. Russell, Microbiology and Immunology, and his research colleague gained a better understanding of how tuberculosis survives inside human defense cells. Using advanced genetic techniques, the researchers discovered that unlike many bacterial pathogens, Mycobacterium tuberculosis does not react when immune system cells called macrophages initially make contact. The bacterium’s genes instead become activated minutes after the pathogen is enveloped by a macrophage and contained in one of its membrane-bound compartments called vacuoles. Increased acidity inside the vacuoles serves as the trigger for M. tuberculosis genes to express proteins. The research also compared the responses of M. tuberculosis and a live-bacterial tuberculosis vaccine, Bacillus Calmette-Guerin (BCG). It found that the two bacteria may respond differently to the same stimulus and that BCG appears less capable of protecting itself once inside a macrophage. The study is part of a larger plan to understand the processes that allow the M. tuberculosis bacteria to survive within macrophages in order to develop faster and more effective drugs to fight tuberculosis, which currently kills two million people worldwide each year. Existing drugs require six to nine months to treat the active disease, which invades the lungs.