They are called chimeras. In a lyrical sense, that is what we have created,' said research leader Galipeau, who is a world-renowned expert on cell regeneration.

'GIFT15 is a new protein hormone composed of two distinct proteins, and when they're stuck together they lead to a completely unexpected biological effect,' he said.

This effect converts B-cells - a common form of white blood cell normally involved in immune response - into powerful immune-suppressive cells, he added.

The Canadian said naturally-occurring immune-suppressing B-cells are almost unknown in nature and the notion of using them to control immunity is very new.

He said: 'GIFT15 (the new treatment) can take your normal, run-of-the-mill B-cells and convert them into these super-powerful B-regulatory cells.

'We took normal B-cells from mice, and sprinkled GIFT15 on them, which led to this Jekyll and Hyde effect. And when we gave them back intravenously to mice ill with multiple sclerosis, the disease went away.'

He said there were no significant side-effects in the mice, and the treatment was fully effective with a single dose.

The research leader said multiple sclerosis must be caught in its earliest stages to be reversed by the new treatment, though clinical studies are needed to test its efficacy and safety in humans.

The research has been published this week in the journal Nature Medicine.