Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi won the 2025 Nobel Prize in Physiology or Medicine for key discoveries about peripheral immune tolerance and regulatory T cells, which guard against autoimmune disease
The 2025 Nobel Prize in Physiology or Medicine was awarded Monday to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their “fundamental discoveries relating to peripheral immune tolerance,” the Nobel Assembly said in Stockholm.
Their work revealed a class of immune cells known as regulatory T cells, which function as the immune system’s “security guards” to prevent immune cells from attacking the body itself.
“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 Kämpe, chair of the Nobel Committee.
Sakaguchi, reached by phone at his lab, said, “I feel it is a tremendous honour.”
Brunkow is affiliated with the Institute for Systems Biology in Seattle, Ramsdell works with Sonoma Biotherapeutics in San Francisco, and Sakaguchi is a professor at Osaka University in Japan.
The laureates will share a prize sum of 11 million Swedish kronor and receive gold medals at a December ceremony in Stockholm