Photo :webshot. 

October 7, 2025

Anna Murray 

Three scientists have been awarded the 2025 Nobel Prize in Physiology or Medicine for uncovering how the immune system protects us from thousands of different microorganisms that attempt to invade our bodies. Their work also explains how the body prevents the immune system from malfunctioning and attacking its own tissues — a process known as
peripheral immune tolerance.

At a ceremony held on October 6 at the Karolinska Institute in Stockholm, Sweden, the Nobel Committee announced that Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi would share the prize for their groundbreaking research on the human immune system.

In 1995, Japanese immunologist Shimon Sakaguchi identified a previously unknown type of T lymphocyte. In the early 2000s, American researchers Mary E. Brunkow and Fred Ramsdell built upon
Sakaguchi’s discovery, identifying a gene mutation in mice known as Foxp3. Later, in 2003, Sakaguchi linked their findings to his earlier work, demonstrating that the Foxp3 gene regulates the development of“regulatory T cells,” which play a key role in maintaining immune balance.