Scientists discover natural molecules that help calm immune cells

First author on the JEM publication, Monash BDI PhD student Mohamed Abdelaal, and co-senior and co-corresponding author, Dr. Wael Awad.
First author on the JEM publication, Monash BDI PhD student Mohamed Abdelaal, and co-senior and co-corresponding author, Dr. Wael Awad.

Researchers have uncovered a surprising way the human body helps keep its immune system in check. The study found that when the body breaks down vitamin B2 (riboflavin), it produces natural molecules that can reduce the activity of MAIT cells - specialised immune cells involved in inflammation.

Co-led by Monash Biomedicine Discovery Institute (BDI) and University of Melbourne researchers, and published in the Journal of Experimental Medicine, the discovery shows that our bodies naturally produce molecules that can suppress MAIT cell activity, filling a major gap in understanding how the body maintains immune balance. Previously, research focused on how bacteria activate these cells, but little was known about the body’s own regulatory mechanisms.

These molecules interact with an immune sensor called MR1, which normally helps activate MAIT cells. Instead of boosting MR1 activity like vitamin-related molecules do, the body’s own molecules keep MR1 inside the cell, lowering its presence on the surface and dampening the immune response.

“Our findings reveal a natural mechanism that prevents unnecessary immune activation and inflammation,” said Mohamed Abdelaal, a PhD student with the Monash BDI and first author of the study.

“Understanding this process opens the door to new ways of controlling inflammation and immune-related diseases, by targeting overactive immune responses,” he said.

The study highlights a new dimension of MR1 biology and its role in immune homeostasis, paving the way for future research into how metabolic byproducts influence immunity.

Next steps include testing these molecules in living systems and exploring drug-like compounds that fine-tune MAIT cell activity, potentially leading to new therapeutic targets for immune disorders.

This study was co-led by Dr Wael Awad from Monash University’s Biomedicine Discovery Institute, and Dr Nicholas Gheradin from the Peter Doherty Institute for Infection and Immunity, University of Melbourne.

Read the full paper published in the Journal of Experimental Medicine, titled The antigen presenting molecule MR1 binds host-generated riboflavin catabolites.
DOI: 10.1084/jem.20250711

GENERAL MEDIA ENQUIRIES

For more Monash media stories, visit our news and events site
Monash Media
E: media@monash.edu
T: +61 (0) 3 9903 4840

About the Monash Biomedicine Discovery Institute at Monash University

Committed to making discoveries that will relieve the future burden of disease, Monash Biomedicine Discovery Institute at Monash University brings together more than 120 internationally renowned research teams. Spanning seven discovery programs across Cancer, Cardiovascular Disease, Development and Stem Cells, Infection, Immunity, Metabolism, Diabetes and Obesity, and Neuroscience, Monash BDI is one of the largest biomedical research institutes in Australia. Our researchers are supported by world-class technology and infrastructure, and partner with industry, clinicians and researchers internationally to enhance lives through discovery.