Nobel Prize In Medicine Awarded To Team Who Discovered How Immune System Is Kept In Check
Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi have been awarded the Nobel Prize in Physiology or Medicine 2025.
Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi have been 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. Their work enables new treatments for cancer, autoimmune diseases, and improves transplant success.
Brunkow is a Senior Program Manager at the Institute for Systems Biology in Seattle, US. Fred Ramsdell holds the position of Scientific Advisor at San Francisco-based Sonoma Biotherapeutics. Shimon Sakaguchi is a Professor at the Immunology Frontier Research Center of Osaka University in Japan.
The laureates identified the immune system's security guards known as '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,” Olle Kämpe, chair of the Nobel Committee, said in a statement.
Understanding The Immune System
Previously, many researchers were convinced that immune tolerance only developed due to potentially harmful immune cells being eliminated through a process called central tolerance. In 1995, Shimon Sakaguchi showed that the immune system is more complex and discovered a previously unknown class of immune cells, which protect the body from autoimmune diseases.
Mary Brunkow and Fred Ramsdell made the other key discovery in 2001, when they presented the explanation for why a specific mouse strain was particularly vulnerable to autoimmune diseases. They had discovered that the mice have a mutation in a gene that they named 'Foxp3'. They also showed that mutations in the human equivalent of this gene cause a serious autoimmune disease, IPEX.
Two years after this, Sakaguchi was able to link these discoveries. He proved that the Foxp3 gene governs the development of the cells he identified in 1995. These cells, now known as regulatory T cells, monitor other immune cells and ensure that our immune system tolerates our own tissues.
"The laureates’ discoveries launched the field of peripheral tolerance, spurring the development of medical treatments for cancer and autoimmune diseases. This may also lead to more successful transplantations. Several of these treatments are now undergoing clinical trials," the statement from Nobel Committee said.
