Mycobacterium tuberculosis, the microbe responsible for TB

NIAID

Scientists have discovered how the body's immune system detects the tuberculosis bacterium, a finding that could aid the development of novel vaccines and drugs to artificially trigger an immune response.

The research was published in Science last week (19 October).

The bacterium Mycobacterium tuberculosis infects one-third of the world's population and is responsible for two million deaths each year. 

Paul Lehner of the UK-based Cambridge Institute for Medical Research and colleagues identified a receptor on the host cells known as CCR5 that triggers the immune cells' response to tuberculosis (TB). 

The team demonstrated that without this receptor, Mycobacterium tuberculosis was able to thrive inside host cells, as the immune cells did not receive the signal from CCR5 to attack them.

"These results describe a novel mechanism whereby Mycobacterium tuberculosis communicates with the human immune system," says Beate Kampmann at the UK-based Wellcome Centre for Clinical Tropical Medicine, one of the study's authors.

"Another piece of this complex jigsaw has been filled in, which will help us to target TB with very specific drugs or vaccines," Kampmann added.

Sanjeev Krishna of the Centre for Infection at St George's Hospital Medical School in London, United Kingdom, says the research describes an important and novel link between the immune system and the pattern-recognition based mechanisms that respond to infections.

He says it may be possible to improve the immune responses to TB, a treatment "desperately needed for many vaccines that are being developed for infections that are so common in developing countries."

Speaking to SciDev.Net, David Moore of the Wellcome Centre said: "Significant new advances in our understanding of the basic biology of the pathogen-host interaction in tuberculosis, such as this, are fairly infrequent."

"If these data start to shed light on the puzzle that is latent M tuberculosis infection, as well as the relatively unpredictable short-term outcome of acute infection then the implications for control in all settings are certainly exciting."

Reference: Science 314, 5798 (2006) pp. 454 - 458