The 2025 Nobel Prize in Physiology or Medicine has been awarded to American scientists Mary Brunkow and Fred Ramsdell, and Japanese scientist Shimon Sakaguchi, for their groundbreaking discoveries concerning peripheral immune tolerance. This year’s prize recognizes their work on how the immune system keeps itself in check, a crucial mechanism that prevents it from attacking healthy cells ¹.
According to the Nobel Assembly, the trio’s findings have laid the foundation for a new field of research and spurred the development of new treatments for cancer and autoimmune diseases. “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 ².
Shimon Sakaguchi, a distinguished professor at Osaka University, expressed his surprise at the news, saying, “I believe the time will come when cancer is no longer a scary disease, but a curable one.” His work on regulatory T cells has been instrumental in understanding how the immune system regulates itself ¹.
## The Discoveries
The scientists discovered that regulatory T cells, a type of white blood cell, act as the immune system’s security guards. These cells prevent immune cells from attacking the body’s own tissues. Mary Brunkow and Fred Ramsdell identified the FOXP3 gene, which controls immune regulation and is crucial for the development of regulatory T cells ³.
## Impact on Medicine
The Nobel Committee noted that more than 200 clinical trials are ongoing, investigating therapies that target peripheral immune tolerance. These trials hold promise for treating autoimmune diseases, such as rheumatoid arthritis and type 1 diabetes, as well as cancer ⁴.
The prize winners will share the 11 million Swedish kronor ($1.2 million) award, and each will receive a gold medal. The Nobel Prize in Physiology or Medicine is considered one of the most prestigious awards in the scientific community, recognizing outstanding contributions to medical research ¹.