The 2025 Nobel Prize in Medicine: How the Immune System Learns to Protect the Body Without Turning Against It

This life-saving discovery has been awaited for decades.

The 2025 Nobel Prize in Physiology or Medicine was awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for revealing the mechanism that explains why our immune system does not attack itself.

Their work revealed a fundamental mystery — the mechanism of peripheral immune tolerance, which prevents the immune system from destroying healthy cells.

Regulatory T cells (Tregs) play a key role here—a special type of immune cell that restrains the body's excessive response.

In 1995, Sakaguchi first discovered these cells and proved that they prevent autoimmune diseases.

Later, Brankou and Ramsdell found the FOXP3 gene, which controls the function of Treg cells, while studying a rare autoimmune disease in children.

The breakthrough came when Sakaguchi proved that FOXP3 is the “master switch” that turns on immune restraint.

This was a breakthrough that changed the understanding of immune system self-control.

Today, the laureates' discovery has become the basis for:

• treating autoimmune diseases (such as type 1 diabetes, multiple sclerosis, and rheumatoid arthritis), improving transplant engraftment,

• and even enhancing cancer immunotherapy — when it is necessary to “turn off” the immune brake in tumors.

What was once a mystery has now become one of the most influential discoveries in modern immunology.

Детальніше