A US team has found that inactivating chemicals called chemokines can halt the damage that MS causes to the protective coating of nerves in the brain and spinal cord.

It is this damage to the myelin sheath that causes a variety of symptoms such as numbness, weakness and paralysis.

Essentially, it is caused by a malfunction of the immune system, which begins to attack the body itself. Nobody knows what triggers this malfunction.

However, research has shown that the cerebrospinal fluid found in the central nervous system of MS patients often contains abnormally high levels of chemokines.

Rabbit antibodies

These chemicals play a major role in mobilising the cells of the immune system to attack the myelin.

The researchers, led by Dr Thomas Lane, from the University of California, Irvine, tested the theory that targeting chemokines, or the receptors that detect them, might slow down or halt the attack on the myelin, giving the nerve coating a chance to recover.

New Scientist magazine reports that the team created antibodies that bind to a chemokine called CXCL10 and inactivate it.

They targeted CXCL10 specifically because previous studies have shown that levels of the chemical rise sharply during MS attacks.

When the antibodies were injected into mice with a condition similar to MS, they helped to slow demyelination, and even appeared to allow myelin to regrow.

As a result, mice that were crippled were able to walk again. However, the reversal of symptoms was not complete and despite continued injections the effects lasted only a few days.

This is probably because the CXCL10 antibodies, which came from rabbits, provoked an immune response that neutralised them.

Dr Lane's team is now repeating the tests with a different version of the antibody.

Human tests needed

Dr Richard Ransohoff, an expert in chemokines and MS at the Lerner Research Institute in Cleveland, Ohio, said further tests were needed to see if the same results could be repeated in humans.

But he said: "In terms of treating the inflammation aspects, Lane's work is as promising as anything one can imagine."

Other researchers are pursuing similar strategies to Dr Lane's team.

Universities and companies are investigating seven chemokines and five different chemokine receptors.

However, Dr Ransohoff warned that tinkering with chemokines was a risky business.

"These molecules provide necessary immune functions. Completely eliminating them isn't safe."

A spokesman for the UK MS Society told BBC News Online: "This sort of work shows promise, but obviously there is some way to go before we know whether there is any prospect of taking these drugs into human trials."

The research is published in the Journal of Immunology.