Scientists Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi won the 2025 Nobel Prize in Physiology or Medicine for “their discoveries concerning peripheral immune tolerance,” the award-giving body said on Monday.
This year’s prize “relates to how we keep our immune system under control so we can fight all imaginable microbes and still avoid autoimmune disease,” said Marie Wahren-Herlenius, a rheumatology professor at the Karolinska Institute in Stockholm.
Brunkow is a senior program manager at the Institute for Systems Biology in Seattle. Ramsdell is a scientific adviser for Sonoma Biotherapeutics in San Francisco. Sakaguchi is a distinguished professor at the Immunology Frontier Research Center at Osaka University in Japan.
“Their 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,” the prize-awarding body said in a statement.
The laureates identified so-called regulatory T cells, which act as the immune system’s security guards that keep immune cells from attacking our own body, it added.
After announcing the winners, the institute’s Thomas Perlmann said he had only been able to break the news to one of the three, reaching Sakaguchi by phone at his lab.
“He sounded incredibly grateful, expressed that it was a fantastic honour and he was quite taken by the news,” added Perlmann.
The Nobel Prize was created by wealthy Swedish chemist and entrepreneur Alfred Nobel, who in his will dictated that the bulk of his estate should be used to fund “prizes to those who, during the preceding year, have conferred the greatest benefit to humankind.”
Peace prize to be awarded Friday
Nobel is best known as the inventor of dynamite, but also wrote poetry and drama and could speak Russian, French, English and German by the age of 17. The five original prize categories reflect the interests closest to his heart.
The Nobel awards, which are also handed out for outstanding achievements in physics, chemistry, literature and peace, come with a prize amount of 11 million Swedish crowns ($1.6 million Cdn).
Prizes for chemistry and physics will be awarded Tuesday and Wednesday, literature on Thursday and the peace prize on Friday. The economics prize will be announced Oct. 13.
Notable Nobel laureates include scientists Albert Einstein and Marie Curie, authors Ernest Hemingway and Albert Camus, and inspirational figures such as Nelson Mandela, Martin Luther King Jr. and Mother Teresa.
The Nobel prizes are presented to the laureates on Dec. 10, the anniversary of Nobel’s death.
