Nobel Prize in Physiology or Medicine 2025 awarded to immune system researchers

Summary

Navigate to: Summary- Mary E. Brunkow- Fred Ramsdell- Shimon Sakaguchi Prize announcement Press release Advanced information Popular information EnglishEnglish (pdf)SwedishSwedish (pdf) 6 October 2025 The Nobel Assembly at Karolinska Institutet has decided to award the 2025 Nobel Prize in Physiology or Medicine to: Mary E. BrunkowInstitute for Systems Biology,Seattle, USA Fred RamsdellSonoma Biotherapeutics,San Francisco, USA Shimon SakaguchiOsaka University,Osaka, Japan “for their discoveries concerning peripheral immune tolerance” They discovered how the immune system is kept in check The body’s powerful immune system must be regulated, or it may attack our own organs. Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi are awarded the Nobel Prize in Physiology or Medicine 2025 for their groundbreaking discoveries concerning peripheral immune tolerance that prevents the immune system from harming the body. Every day, our immune system protects us from thousands of different microbes trying to invade our bodies. These all have different appearances, and many have developed similarities with human cells as a form of camouflage. So how does the immune system determine what it should attack and what it should defend? Mary Brunkow, Fred Ramsdell and Shimon Sakaguchi are awarded the Nobel Prize in Physiology or Medicine 2025 for their fundamental discoveries relating to peripheral immune tolerance. The laureates identified the immune system’s security guards, regulatory T cells, which prevent immune cells from attacking our own body. “Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases,” says Olle Kämpe, chair of the Nobel Committee. Shimon Sakaguchi was swimming against the tide in 1995, when he made the first key discovery. At the time, many researchers were convinced that immune tolerance only developed due to potentially harmful immune cells being eliminated in the th...