Trio win Nobel in medicine for discovering peripheral immune tolerance

Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi were awarded the 2025 Nobel Prize in Physiology or Medicine on Monday for their discoveries concerning peripheral immune tolerance, said the Nobel Committee in a press release.

The laureates identified the immune system’s security guards, regulatory T cells, which prevent immune cells from attacking our own body.

“Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases,” said Olle Kämpe, chair of the Nobel Committee.

The Nobel Assembly at Sweden's Karolinska Institute said the trio's work has had far-reaching clinical implications, paving the way for new treatments for autoimmune diseases and cancer, and potentially improving the success of transplantations.

Mary E. Brunkow, born 1961. Ph.D. from Princeton University, Princeton, USA. Senior Program Manager at the Institute for Systems Biology, Seattle, USA.

Fred Ramsdell, born 1960. Ph.D. 1987 from the University of California, Los Angeles, USA. Scientific Advisor, Sonoma Biotherapeutics, San Francisco, USA.

Shimon Sakaguchi, born 1951. M.D. 1976 and Ph.D. 1983 from Kyoto University, Japan. Distinguished Professor at the Immunology Frontier Research Center, Osaka University, Japan.

The laureates will share the prize sum of 11 million Swedish kronor (about 1.17 million U.S. dollars).

The Nobel Prize in Physiology or Medicine has been awarded since 1901. Last year's prize went to American scientists Victor Ambros and Gary Ruvkun for discovering microRNA and its role in gene regulation.