Portraits of the 2025 Nobel Prize in Physiology or Medicine laureates Mary E. Brunkow (L), Fred Ramsdell (C) and Shimon Sakaguchi are shown on a screen during the announcement of the prize at the Karolinska Institute in Stockholm, Sweden, on Oct. 6, 2025. 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, the Nobel Assembly at Sweden's Karolinska Institute announced. (Xinhua/Peng Ziyang)

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.

"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 Kampe, 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.

Brunkow, born in 1961, is a senior program manager at the Institute for Systems Biology in the United States. Ramsdell, born in 1960, serves as a scientific advisor at Sonoma Biotherapeutics, also in the United States. Sakaguchi, born in 1951, is a professor at the Immunology Frontier Research Center of Osaka University in 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.