Scientists have detected the precise biochemical key that wakes up the body's immune cells and sends them into action to fight bacteria and fungi.
The finding provides a deeper understanding of our first line of defence, and what happens when it goes wrong.
It will lead to new ways of diagnosing and treating inflammatory bowel disease, peptic ulcers and even TB, and may pave way for novel protective vaccines, researchers said.
"Our intestines, lungs and mouths are lined with mysterious immune cells that make up to ten per cent of the T cells in our immune system," said Professor James McCluskey Deputy Vice-Chancellor (Research) at University of Melbourne.
"Last year we showed that these cells act as sentinels against invading bacteria and fungi. Now we've identified the precise biochemical key that wakes up these sentries and sends them into action," he said.
The immune cells, known as mucosal-associated invariant T cells (MAITS), initiate the immune system's action against foreign invaders when they are exposed to vitamin B2, which is made by bacteria and fungi.
"MAIT cells are a discovery so recent that they have not even made it into the textbooks. Most doctors know nothing about them. Yet they constitute about one cell in ten of the body's T cells and half of all the T cells in the liver," McCluskey said.
Professor David Fairlie of the Institute for Molecular Bioscience at the University of Queensland said the findings may be a valuable clue to disease pathways and new drug therapies.
The research was published in the journal Nature.
