TB’s secret weapon exposed

The germ which causes tuberculosis has a cloaked weapon that weakens the body's defences, according to a paper by Indian scientists published in the May issue of the journal Nature Immunology.

Mycobacterium tuberculosis's secret arm has been dubbed early secreted antigenic target protein, or ESAT-6.

Joyoti Basu of the Bose Institute in Calcutta and colleagues found that purified ESAT-6 interfered with a key white blood cell that alerts the immune system to an intruder.

The sentry cell, known as a macrophage, is de-activated when ESAT-6 latches onto its surface at a docking site called TLR2.

Blocking the interaction between ESAT-6 and TLR2 throws up a good path of exploration for new TB treatment, the paper suggests.

Around 1.6 million people die from TB each year, making tuberculosis the deadliest infectious disease on the planet after Aids and ahead of malaria, according to the UN's World Health Organisation (WHO). – (Sapa-AFP)

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A-Z of Tuberculosis

May 2007