NEW ORLEANS University of Michigan microbiologists have created a virtual model of the human immune system that runs "in silico" to study what happens inside the lungs after people inhale Mycobacterium tuberculosis, the bacterium that causes TB.

The computer model is helping scientists learn more about this ancient pathogen, and why some people are able to fight off the infection, while others get sick. U-M scientists believe the answer could be hidden inside structures called granulomas, which immune cells build to surround and contain invading M. tuberculosis bacteria.

"Granulomas are the hallmark of tuberculosis," says Denise Kirschner Ph.D., an associate professor of microbiology and immunology in the U-M Medical School. "It's the immune system's fail-safe response to infection. If the immune system can't clear the pathogen, it gets out the masonry and walls it off."

Kirschner presented research results and an analysis of time-lapse computer animations showing granuloma formation at a May 26 seminar during the American Society for Microbiology's annual meeting held here this week.

"M. tuberculosis has been living with people for at least 4,000 years," says Kirschner. "Because the bug has had all those years to get to know us so well, it has evolved several effective ways to circumvent the immune system's ability to detect and kill invading pathogens. Scientific knowledge of how the immune system interacts with M. tuberculosis is slowly improving, but we are far from prevention or an effective vaccine. It's important to understand TB, because the disease is a serious and growing public health problem."

According to Kirschner, approximately 2 billion people worldwide are infected with M. tuberculosis, and the disease kills about 3 million people every year. In the early stages of infection, tuberculosis can be treated with powerful antibiotics, but there is no cure. And multi-drug-resistant strains, which are essentially
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Contact: Sally Pobojewski
pobo@umich.edu
734-615-6912
University of Michigan Health System
26-May-2004