US and Japanese scientists win 2025 Nobel Prize for immune tolerance research

Mary E Brunkow, Fred Ramsdell, and Shimon Sakaguchi have been awarded the 2025 Nobel Prize in Physiology or Medicine for discovering how the immune system prevents attacks on the body’s own tissues — a process known as peripheral immune tolerance.

The Nobel Assembly at the Karolinska Institutet in Stockholm announced the award on Monday, recognizing the scientists for revealing the mechanisms that keep immune responses in check. Their findings have transformed understanding of how the body avoids self-destruction and paved the way for treatments for autoimmune diseases such as multiple sclerosis and type 1 diabetes.

Brunkow, born in 1961, earned her PhD from Princeton University and is Senior Program Manager at the Institute for Systems Biology in Seattle. Ramsdell, born in 1960, holds a PhD from the University of California, Los Angeles, and serves as Scientific Advisor at Sonoma Biotherapeutics in San Francisco.

Sakaguchi, born in 1951, received his MD and PhD from Kyoto University and is Distinguished Professor at Osaka University’s Immunology Frontier Research Center.

The three laureates will share 11 million Swedish kronor (about $1 million).

The Nobel Prize in Physiology or Medicine has been awarded 115 times to 229 recipients since 1901. Last year’s prize went to American scientists Victor Ambros and Gary Ruvkun for their discovery of microRNA — tiny genetic molecules that regulate cellular activity.

The Nobel Peace Prize will be announced on Friday, followed by the Prize in Economic Sciences next Monday. The award ceremony will take place on December 10, the anniversary of Alfred Nobel’s death in 1896.