Hope for new TB treatment

By BBC News Online's Damian Carrington

The system of chemical signals used by the bacteria that cause tuberculosis (TB) has been discovered and may help scientists create future vaccines.

A third of the world's population may carry the TB bacterium in its dormant form, but they cannot be treated because anti-TB drugs only work if the bacteria are active. Furthermore, the occurrence of TB is rising in many major cities and multi-drug resistant strains are now appearing.

Professor Mike Young, of the University of Wales at Aberystwyth, was studying bacteria related to TB when he discovered that they produce a chemical "alarm call" that rouses other bacteria of that species from dormancy.

Speaking at the British Association's Festival of Science in Sheffield, UK, Professor Young said: "The protein is not just a wake-up call but also a growth factor for the bacteria."

Because all 4,000 genes of the TB bacterium have been sequenced, Professor Young could immediately see that the TB bug produces five growth factor proteins with similar properties.

Possible targets

He sees a number of attractive possibilities that could result from further investigation of these proteins, though none are likely to reach fruition in the near future.

• If the human immune system can be persuaded to recognise the proteins, it could lead to TB vaccines.
• Understanding how the proteins control growth and finding ways to block them could make it possible to prevent an infection developing into the disease.
• The proteins may be useful as early signs of infection for rapid diagnosis.

A further, apparently alarming, suggestion by Professor Young is that the proteins could be used to wake up a dormant infection. The reason this could be beneficial is that dormant TB often flares up when a person's immune system is weak, as in old age or due to the development of Aids.

Forcing the bacteria into an active state while a person is otherwise healthy would allow the bugs to be attacked by drugs and cleared.

Tuberculosis affects more people than Aids and malaria combined. The disease is expected to kill 40 million people over the next 20 years if a vaccine is not found.