Medicine Nobel Prize awarded for discovery of immune system regulators

• 2025 Nobel Prize in Medicine awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi.
• Honored for discovering regulatory T-cells that prevent the immune system from attacking the body.

The 2025 Nobel Prize in Physiology or Medicine has been awarded to American researchers Mary E. Brunkow and Fred Ramsdell, as well as Japanese scientist Shimon Sakaguchi. 

The trio were awarded for their groundbreaking discoveries on how the body controls the immune system and prevents it from attacking itself.

Read more: UNHCR cuts 5,000 jobs since January amid funding crisis

Announcing the prize Monday in Stockholm, the Nobel Committee said the award recognizes the researchers’ discoveries related to peripheral immune tolerance.

While the body’s immune system must be powerful enough to fight infections, it also needs to be tightly regulated to avoid attacking healthy tissues, a malfunction that leads to autoimmune diseases, the research explained.

At the heart of their achievement is the discovery of the immune system’s guardian cells, known as regulatory T-cells (Tregs), which act as brakes that stop other immune cells from attacking the body’s own tissues.

According to the Nobel Committee, the discoveries by Brunkow (63), Ramsdell (64), and Sakaguchi (74) not only deepened scientific understanding of immune regulation but also laid the foundations for an entirely new field of research.

Their work has paved the way for the development of new and innovative treatments for serious diseases such as cancer and autoimmune disorders.

The award includes a diploma, a gold medal, and a cash prize of 11 million Swedish kronor (approximately USD 1.17 million), to be shared among the three laureates.