BBC
10-22-2006
There were 8,000 cases of TB in the UK last year
A key part of body's defence against tuberculosis has been identified by an international team of scientists. The study in Science found cells in the body have a receptor on their surface which sends out a signal calling for immune system aid when TB is detected.
The researchers say the aim would be to mimic this rallying cry with a vaccine or immune system therapy to help fight the bacterium.
TB experts welcomed the growing attention being paid to the disease.
They said there were 8,000 people infected with TB in the UK last year, up 10% from 2004.
Around 2.5 million people die from the disease around the world each year.
'A piece of the jigsaw'
Scientists have known for some time that when host cells are invaded by this bacterium, they are able to call up additional immune cells to fight TB and try to limit the damage caused.
The team, including researchers from Imperial College London and the Universities of Cambridge and Oxford, identified the CCR5 receptor on the host cells which triggers the immune cells' response.
The scientists found that if CCR5 was not present, the bacteria were able to thrive inside host cells, because immune cells did not receive the signal to attack.
Dr Beate Kampmann, from the Wellcome Trust Centre for Clinical Tropical Medicine and the Department of Paediatrics at Imperial College London, who worked on the research, said: "These results describe a novel mechanism whereby Mycobacterium tuberculosis communicates with the human immune system.
"Another piece of this complex jigsaw has been filled in, which will help us to target TB with very specific drugs or vaccines.
The scientists hope that their findings could lead to a new vaccine or immunotherapy being developed which could artificially kick the immune cells into action in the same way as CCR5, boosting the body's ability to fight TB.
Dr Kampmann added: "We can now test potential vaccines or drug candidates for the desired effect, as we understand better how they should act."
A new way of tackling TB is urgently needed.
The existing BCG vaccine does not offer complete protection, and the current treatment for TB involves taking medication for at least six months.
This means many people do not complete the cause, fuelling the development of multi-drug resistant strains of TB.
Professor Peter Davies, head of the TB unit at Liverpool's Cardiothoracic Centre and a member of the campaign group TB Alert, welcomed the research.
He added: "At last we are getting scientific attention in the battle against TB which, as we all recognise, we are losing.
"There are more deaths and more cases each year.
"We desperately need new vaccines, diagnostics and drugs."