Winners of the Nobel Prize in Physiology or Medicine for 2025.
The 2025 Nobel Prize in Physiology or Medicine was awarded jointly to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their discoveries concerning peripheral immune tolerance. Their work revealed the immune system’s “security guards” — regulatory T cells that prevent other immune cells from attacking the body’s own tissues.
Sakaguchi identified this previously unknown class of cells in 1995. In 2001, Brunkow and Ramsdell showed that mutations in the FOXP3 gene cause severe autoimmune disease; Sakaguchi later demonstrated that this gene controls the development of regulatory T cells. These discoveries opened a new field of research and are guiding treatments for autoimmune diseases and cancer, as well as strategies for more successful transplantation.
