NII Delhi study uncovers key protein behind gut immune balance

New Delhi: Deep within the intestinal wall, beyond where digestion and nutrient absorption occur, are immune outposts called solitary isolated lymphoid tissues, or SILTs. These structures host cells that govern how aggressively the gut reacts to microbes. A weak response lets pathogens take root, while an overactive one causes the immune system to attack the gut — a hallmark of inflammatory disorders like Crohn’s disease.

Now, a new study published in Proceedings of the National Academy of Sciences has traced this balancing act to a protein called RelB.

By engineering mice lacking RelB in these cells, researchers at the National Institute of Immunology (NII), New Delhi, uncovered a paradox: the same protein drives opposite effects depending on its cellular environment and anatomical niche.

The findings shed new light on how the gut maintains immune tolerance and could open new avenues for understanding and treating inflammatory bowel disorders.