Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi

USA / Japan

Nobel Prize in Medicine, 2025Americas

Awarded for

Discoveries about peripheral immune tolerance, which stops the immune system from attacking the body

The story behind the prize

The immune system must attack germs without attacking the body itself. Sakaguchi discovered regulatory T cells, the immune system's 'security guards'; Brunkow and Ramsdell found that a faulty Foxp3 gene causes a severe autoimmune disease in mice and humans. This opens paths to treating autoimmune diseases and cancer and to preventing transplant rejection.

About

Sakaguchi (Japan) identified regulatory T cells; Brunkow and Ramsdell (USA) found the Foxp3 gene that controls them.