The 2025 Nobel Prize in Physiology or Medicine has been awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their groundbreaking discoveries on how the immune system is kept in check. The three scientists, based respectively at the Institute for Systems Biology in Seattle, Sonoma Biotherapeutics in San Francisco, and Osaka University in Japan, were honored “for their discoveries concerning peripheral immune tolerance.”

Their research revealed how the body’s powerful immune system prevents attacks on its own tissues, a process essential for avoiding autoimmune diseases. Sakaguchi identified regulatory T cells, the immune system’s "security guards," while Brunkow and Ramsdell discovered the Foxp3 gene that controls their development.

"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 at the Karolinska Institute.

While the 2018 Nobel laureates James P. Allison and Tasuku Honjo showed how to unleash immune attacks against cancer, Brunkow, Ramsdell, and Sakaguchi revealed how the immune system restrains itself to prevent autoimmune disease. Together, these discoveries reveal two sides of immune balance; one that prevents harmful overreactions and another that can be safely lifted to fight disease.

The 2025 laureates’ findings have launched the field of peripheral immune tolerance, inspiring new treatments for autoimmune diseases and cancer and offering hope for more successful transplant therapies.

Professor Shimon Sakaguchi, one of the three laureates, published an article in MDPI's Cancers journal just a few years ago. Our heartfelt congratulations go to Professor Sakaguchi and his fellow Nobel Prize winners!

Article published with MDPI 

Hyper-Progressive Disease: The Potential Role and Consequences of T-Regulatory Cells Foiling Anti-PD-1 Cancer Immunotherapy
Authors: Christopher Tay, Yamin Qian and Shimon Sakaguchi 
Cancers  2021, 13(1), 48