The 2025 Nobel Prize in Physiology or Medicine has been awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their groundbreaking discovery of regulatory T cells, the peacekeepers of our immune system.

Our immune system is designed to fight harmful germs, but sometimes it gets confused and attacks the body itself. These wrong attacks cause autoimmune diseases like type 1 diabetes, lupus, or multiple sclerosis. The Nobel-winning scientists found that a special group of immune cells, called regulatory T cells or T-regs, stop this from happening.

Dr. Sakaguchi first identified these cells in the 1990s, while Brunkow and Ramsdell later uncovered the key gene behind them, known as FOXP3. This gene acts like a switch that controls how these regulatory cells work. When FOXP3 doesn’t function properly, the immune system loses its balance, leading to serious illnesses.

Their discovery changed how doctors and researchers view immunity. It opened the door to new medical possibilities, from treating autoimmune diseases and improving organ transplants, to developing better cancer immunotherapies that fine-tune the body’s defense system instead of simply boosting or suppressing it.

The Nobel Committee at the Karolinska Institute in Stockholm praised the trio for revealing how our bodies maintain “immune harmony.” Their work reminds the world that true strength often lies not in attack, but in control.