Stockholm, Sweden – Mary E Brunkow, Fred Ramsdell, and Shimon Sakaguchi have been awarded the 2025 Nobel Prize in Physiology or Medicine for their discoveries in peripheral immune tolerance – or in lay terms they discovered how the immune system is kept in check.
The announcement was made on Monday by the Nobel Assembly at the Karolinska Institutet in Stockholm, Sweden.
The trio – two based in the United States and one in Japan – was recognised for their ‘groundbreaking discoveries concerning peripheral immune tolerance’, that prevents the immune system from harming the body.
This critical biological process helps the immune system distinguish between harmful invaders and the body’s own tissues, preventing autoimmune diseases.
Their research has paved the way for advances in treating conditions such as multiple sclerosis, type 1 diabetes, and other immune-related disorders.
Born in 1961, Mary E Brunkow has a PhD from Princeton University in the US. She is a senior programme manager at the Institute for Systems Biology, in Seattle.
Fred Ramsdell, born in 1960, has a PhD from the University of California, Los Angeles and is a scientific advisor, Sonoma Biotherapeutics in San Francisco.
While, Shimon Sakaguchi, born 1951, has an MD and PhD from Kyoto University in Japan. She is a distinguished professor at the Immunology Frontier Research Centre, Osaka University, in Japan.
The winners will receive a prize sum of 11mn Swedish crowns (US$1.2mn), as well as a gold medal from the King of Sweden.

What is the prize’s history?

The Nobel Prize in physiology or medicine has been awarded 115 times to 229 laureates between 1901 and 2024.

Last year’s prize was shared by Americans Victor Ambros and Gary Ruvkun for their discovery of microRNA, which serves as on and off switches inside cells that help control what the cells do and when they do it.

The physics prize will be announced on Tuesday, with the prizes in chemistry being made public on Wednesday, and the literature one on Thursday.

Friday will see the announcement of the Nobel Peace Prize, while the Nobel Memorial Prize in economics will be announced on October 13.

The awards ceremony will be held on December 10, the anniversary of Alfred Nobel’s death. Nobel was a wealthy Swedish industrialist and inventor of dynamite who died in 1896.

Agencies