Overview

• Karolinska Institutet named Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi the 2025 laureates for revealing how the immune system avoids attacking the body.
• Their work identified regulatory T cells and established Foxp3 as the gene that programs their development, resolving how peripheral tolerance prevents autoimmunity.
• The discoveries seeded a new field and inform therapies under clinical evaluation for autoimmune disease, cancer and transplantation, with no approved treatment yet reported.
• At the time of the announcement, the committee reached Sakaguchi but initially could not contact Brunkow or Ramsdell, according to Nobel official Thomas Perlmann.
• The prize totals 11 million Swedish kronor to be shared among the three, with medals and diplomas to be presented at the December 10 ceremony in Stockholm.