Stockholm: The 2025 Nobel Prize in Physiology or Medicine has been awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their discoveries on peripheral immune tolerance — a key mechanism that prevents the immune system from attacking the body’s own tissues.

“They identified the immune system’s security guards, regulatory T cells, thus laying the foundation for a new field of research. The discoveries have also led to the development of potential medical treatments that are now being evaluated in clinical trials,” the Nobel Committee sais in a statement. “The hope is to be able to treat or cure autoimmune diseases, provide more effective cancer treatments and prevent serious complications after stem cell transplants.”

• The Nobel Committee praised the trio for uncovering how regulatory T cells act as “guards” of the immune system, ensuring balance between defense against infections and protection from autoimmune disease.

According to Olle Kämpe, chair of the Nobel Committee, “Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases.”

The laureates’ findings have paved the way for new treatments in autoimmune diseases, cancer, and transplantation medicine, many of which are now advancing through clinical trials.Since its inception in 1901, the Nobel Prize in Medicine has been awarded 115 times to 229 individuals, with Frederick Banting remaining the youngest recipient at just 31 years old.