Vitamin B metabolites produced by Salmonella bacteria can activate the immune system, a study has found, paving the way for new treatments for gut and lung diseases.

Researchers set out to identify what compounds, produced in Salmonella broths, were responsible for activating Mucosal T cells (MAIT) cells. These are important in the gastrointestinal tract and the lungs for protecting against bacterial infections.

They found that specific metabolites of Vitamin B, which are uniquely synthesised by certain bacteria, act as red flags that activate MAIT cells.

This is the first time small organic compounds have been found to activate such immune cells and could lead to a new understanding of immune defence.