The Japan Science and Technology Agency (JST) extends our heartfelt congratulations to Dr. Shimon Sakaguchi, Specially Appointed Professor at the Immunology Frontier Research Center, the University of Osaka, on being awarded the 2025 Nobel Prize in Physiology or Medicine.

Dr. Sakaguchi has been awarded the prize this year for his discovery of regulatory Treg cells. He has devoted many years to studying immune self-tolerance—the mechanism by which the immune system attacks only foreign entities, such as viruses, while avoiding damage to the body’s own tissues. Dr. Sakaguchi was the first in the world to identify regulatory Treg cells, which play a crucial role in maintaining self-tolerance. Furthermore, his pioneering molecular-level research on the characteristics and functions of Treg cells has made a major contribution to elucidating the mechanisms of immune self-tolerance.

Researchers around the world are studying the development, induction, and proliferation of regulatory Treg cells, while pharmaceutical companies are actively pursuing drug discovery based on the functional regulation of these cells. Their potential applications extend beyond cancer and immune disorders to chronic diseases such as cardiovascular disease and diabetes, and the discovery of Treg cells is expected to lead to the development of groundbreaking new therapies.

We would like to once again extend our heartfelt congratulations to Dr. Shimon Sakaguchi on receiving the Nobel Prize. The Japan Science and Technology Agency (JST) will continue to redouble its efforts to contribute to the further advancement of science and technology in Japan.

October 6, 2025
Kazuhito Hashimoto
President
Japan Science and Technology Agency (JST)