Diseases like CJD are caused by the abnormal folding of proteins called prions

But treatment is expected to be very damaging to the immune system, and there is so far no certainty that it will be effective on humans.

Spongiform diseases such as BSE and CJD are caused by the abnormal folding of nerve-tissue proteins, called prions, which lead to the build up of insoluble deposits building up within brain cells, which then no longer function properly and die.

An international team of researchers reports in the journal Science that the prions seem to be produced by immune cells in the spleen.

And they now believe they may be able to confine the prions to the spleen, thus preventing the development of the symptoms of CJD.

'Interesting development'

To mature and stay healthy, the immune cells, called follicular dendritic cells (FDCs), need the help of a signalling molecule which is found on another kind of cell.

It is my duty to give some lymphatic tissue to make myself a guinea pig

Annie McVey, mother of CJD victim

In experiments on mice infected with scrapie, the Swiss, American and British researchers managed to deactivate the signalling cell.

Annie McVey, whose 15-year-old daughter Claire died from CJD in January, has already put herself forward to act as a guinea pig.

She told Channel 4 News: "She said to me at one point, `If they find a cure, even if it is really painful, and they come and tell you, Mum, tell them yes'.

"There may be a few people that for humanitarian reasons would be prepared to be guinea pigs, but perhaps it will be the families who have lost someone who will think, 'It is my duty to give some lymphatic tissue to make myself a guinea pig'."

Gill Turner from the CJD Support Network said: "We welcome any research that furthers the understanding of this disease. "It sounds like this could be another piece of the jigsaw."

Dr James Ironside, of the Edinburgh-based CJD Surveillance Unit, said: "The next big challenge will be to take this approach and see if it could be used on humans and to develop a way of identifying on whom the approach should be used.

"We are at the beginning of this very interesting development."