MELBOURNE researchers have discovered the “trigger point” for coeliac disease, unlocking for the first time the molecular interaction the body launching its immune response against gluten.

By uncovering how the “toxin” — the wheat protein gliadin in gluten — causes the reaction, researchers hope this will lead to better treatments and diagnostic tests for the one in 70 Australians with the incurable disease.

It is estimated a further 80 per cent of cases — or 330,000 people — remain undiagnosed from the lifelong condition, in which the ingestion of wheat, rye and barley damages the bowel, limits nutrient absorption and often causes infertility.

Researchers from Monash University, the University of Melbourne and Leiden University in the Netherlands used studies conducted at the Australian Synchrotron to uncover this molecular “docking” mechanism.

Monash’s Dr Hugh Reid said coeliac disease was an immune response against gluten, in which certain T cells interpreted it as a foreign and toxic substance they must fight.

Dr Reid said their findings, published today in the journal Nature Structural and Molecular Biology, deciphered the immune response that occurred in 95 per cent of coeliac sufferers who carried one of the two gene linked to disease susceptibility.

“It’s the first time we’ve been able to observe the actual triggering point of initiation of the response in coeliac disease,” Dr Reid said.

“We’d like to try to interfere with this interaction with therapeutics, like a vaccine, that could turn off the immune response.”

Dr Reid said they would continue to work with US biotech company Immusan T, which was also involved in the study, to develop a vaccine against coeliac disease.