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A Safer Shot at TB
by Nancy Ross-Flanigan
While trying to understand tuberculosis bacteria genes, researchers discovered a safe way to shut down the bacteria.
A collage of collected wisdom adorns the bulletin board outside the office of HHMI investigator William R. Jacobs, Jr. Neatly printed on strips of paper are quotations from Albert Einstein, Nelson Mandela, Carl Sagan—even musician and humorist Kinky Friedman. A Louis Pasteur quote is prominent in the montage: “In the fields of observation chance favors only the prepared mind.”
That familiar aphorism took on new significance for Jacobs and then graduate student Kari Sweeney when, poring over data from what seemed a failed experiment in 2006, they had a flash of insight that led them to a promising candidate vaccine for tuberculosis (TB) and perhaps other deadly diseases.
“Until now, we’ve only been able to slow the growth of TB bacteria,” says Jacobs. “This is the first time anyone has shown that it’s possible to kill the bacteria with a vaccine.”
So far Jacobs, Sweeney, and colleagues at Albert Einstein College of Medicine have tested the candidate vaccine only in mice, but the results, published online September 4, 2011, in Nature Medicine, are encouraging. The new vaccine cleared TB bacteria from infected tissues in some of the mice, a feat no other TB vaccine has accomplished.
What’s more, the approach might eventually be used to create a super-vaccine that could provide lifelong protection against a variety of diseases, such as malaria, herpes, and HIV, in addition to TB.
TB, an infectious disease caused by Mycobacterium tuberculosis, annually accounts for 2–3 million deaths worldwide. One-third of the world’s population is infected with the bacterium, but most infected people don’t get sick because their immune system keeps the pathogen in check. However, people with a weakened immune system, such as those with HIV/AIDS, are highly susceptible to the bacterium. In Africa and other places with staggering rates of HIV infection, co-infection with TB is a serious problem. To make matters worse, strains of M. tuberculosis have become resistant to every drug used to treat TB, and the only available vaccine doesn’t always protect against the disease.
Illustration: VSA Partners