An immune system protein shows promise as a potential treatment for Alzheimer's disease, early research has shown.

Scientists found that the signalling molecule, called interleukin 33 (IL-33), can reverse symptoms of Alzheimer's and mental decline in mice.

Professor Eddy Liew, from the University of Glasgow, said: "Alzheimer's disease currently has an urgent unmet clinical need. We hope that our findings can eventually be translated into humans.

"IL-33 is a protein produced by various cell types in the body and is particularly abundant in the central nervous system. We carried out experiments in a strain of mouse which develop progressive AD-like disease with ageing.

"We found that injection of IL-33 into aged .. mice rapidly improved their memory and cognitive function to that of the age-matched normal mice within a week."

IL-33 appears to work by mobilising immune cells in the brain to remove protein fragment clumps called beta-amyloid plaques that are a hallmark of Alzheimer's.

It also seems to reduce inflammation in brain tissue.

Prof Liew added: "The relevance of this finding to human Alzheimer's is at present unclear, but there are encouraging hints.

"For example, previous genetic studies have shown an association between IL-33 mutations and Alzheimer's disease in European and Chinese populations. Furthermore, the brain of patients with Alzheimer's disease contains less IL-33 than the brain from non-Alzheimer's patients."

The scientists, whose research appears in the journal Proceedings of the National Academy of Sciences, say they are about to launch a Phase I clinical trial that will test how well human patients tolerate IL-33 therapy.

Professor Gordon Wilcock, from Oxford University, said: "This is additional evidence that the immune system may be implicated in the development of Alzheimer's disease, and really is important since it suggests a potential therapeutic strategy. Nevertheless, we need further research in people since mouse models are a long way from the human condition."