In a breakthrough, researchers have found the exact biochemical key that awakes the body's immune cells and sends them into fight against bacteria and fungi.
This discovery provides a deeper understanding of our first line of defence and what happens when our immune system goes wrong.
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.
"We have identified the precise biochemical key that wakes up these sentries and sends them into action," said James McCluskey, a professor from University of Melbourne.
"This discovery may lead to new ways of diagnosing and treating inflammatory bowel disease, peptic ulcers and even TB and may also lead to novel protective vaccines," he added.
The findings may be a valuable clue to disease pathways and new drug therapies, said the study published in the journal Nature.