• Mary Brunkow, Fred Ramsdell (both US) and Shimon Sakaguchi (Japan) win the 2025 Nobel Prize in Physiology or Medicine for "their discoveries concerning peripheral immune tolerance."
• The Nobel Assembly at the Karolinska Institute awards 11 million Swedish crowns plus a gold medal, with ceremonies in Stockholm and a tradition dating back to the will of Alfred Nobel.
• The prize is cited as laying the foundation for a new field of research and spurring treatments for cancer and autoimmune diseases, per the prize body.
• Winners and prizes sit within a long-standing tradition of Nobel awards, with ceremonies in Stockholm and Oslo for different prizes.

Mary Brunkow and Fred Ramsdell of the United States and Shimon Sakaguchi of Japan have been named the winners of the 2025 Nobel Prize in Physiology or Medicine for “their discoveries concerning peripheral immune tolerance”, announced by the Nobel Assembly at Sweden's Karolinska Institute. The winners are selected by that assembly and receive 11 million Swedish crowns, along with a gold medal presented by Sweden's king, according to reuters, scmp, trtglobal, and channelnewsasia.

The prize description emphasizes that the winners’ discoveries have “laid the foundation for a new field of research and spurred the development of new treatments, for example for cancer and autoimmune diseases,” reinforcing the impact of this work beyond basic science. The Nobel Prizes are said to have been established by Alfred Nobel, first awarded in 1901, with the Economics prize added later, funded by the Riksbank, and the awards administered by expert committees from various institutions, according to reuters, scmp, trtglobal, and channelnewsasia.

The Nobel Prizes are traditionally awarded in Stockholm, with the Peace Prize presented in Oslo, reflecting a historic union between Sweden and Norway, and the ceremonies feature royal participation and formal banquets on December 10, as noted across the reporting, according to reuters, scmp, trtglobal, and channelnewsasia.

Past recipients of the Nobel Prize in Physiology or Medicine include Alexander Fleming (1945), and the prize has recognized major breakthroughs, including those enabling the development of COVID-19 vaccines; last year’s medicine prize went to US scientists Victor Ambros and Gary Ruvkun for microRNA research, as reported by the same outlets, according to reuters, scmp, trtglobal, and channelnewsasia.

The Nobel Prize tradition—often described as among the world’s most prestigious—continues as the medals are awarded in Stockholm, the Peace Prize in Oslo, and continued ceremonies are planned in the days ahead, according to reuters, scmp, trtglobal, and channelnewsasia.