British scientists believe they have identified a key molecule responsible for food allergies.

The Institute of Food Research team in Norwich, headed by Dr Claudio Nicoletti, (right), discovered that the molecule Interleukin-12 is missing in mice which have been bred to be allergic to peanuts.

IL-12 is normally produced by dendritic cells, part of the body's immune system.

Dr Nicoletti found that dendritic cells in the gut of the allergic mice had stopped producing the molecule, leading to an over-production of Immunoglobulin E (IgE).

Normal mice produced the IL-12 which led to a controlled release of IgE.

When IL-12 production was shut off, an imbalance occurred between two groups of T cells: Th1 which is important in pathogen resistance, and Th2 which stimulates antibody production.

"We have identified the missing molecule that normally keeps immune responses under control and appropriate," Dr Nicoletti said.

"We now have a target for a potential treatment for food allergy. We're working with another team of scientists to genetically engineer friendly bacteria that can release IL-12 into the gut.

"Further research will tell us whether giving peanuts together with IL-12 to a person with an allergy might re-establish a normal immune response to peanuts, potentially curing their allergy."

The research was published in the Journal of Allergy and Clinical Immunology.