From the discovery of regulatory T cells to the development of therapies for immune diseases using regulatory T cells

Dr. Shimon Sakaguchi, Distinguished Honorary Professor at the University of Osaka, was awarded the 2025 Nobel Prize in Physiology or Medicine. On December 10, 2025, the Nobel Prize medal was presented to Professor Sakaguchi by His Majesty King Carl XVI Gustaf of Sweden at the award ceremony held in Stockholm, the capital of Sweden. This was a moment of great pride for the people of Japan as well.

The immune system protects the body from external pathogens such as bacteria and viruses and plays a role in eliminating non-self entities that enter from outside. However, this is not always the case. The gastrointestinal tract harbors a large number of intestinal bacteria, which coexist with the host without being eliminated. In addition, a fetus in the mother’s womb is non-self to the mother, yet it is not eliminated. In these cases, immune responses are regulated so that non-self can be appropriately accepted. This state is referred to as immune tolerance. Dr. Sakaguchi discovered regulatory T cells, which function in suppressing immune responses and are key cells responsible for immune tolerance.

It is thought that diseases caused by immune dysfunction can be treated by regulating immune tolerance through the control of regulatory T cell function. In autoimmune diseases such as rheumatoid arthritis, in which the immune system attacks the body’s own tissues, enhancing the function of regulatory T cells can suppress these attacks. In contrast, because cancer cells are recognized as one’s own cells, regulatory T cells protect them from immune attack. In these cases, weakening the function of regulatory T cells is expected to enhance immune responses and potentially eliminate cancer. Dr. Sakaguchi continues to develop therapies for autoimmune diseases and cancer using regulatory T cells at the Immunology Frontier Research Center (IFReC) of the University of Osaka.

Including Dr. Sakaguchi, a total of six Japanese scientists have received the Nobel Prize in Physiology or Medicine to date. Together with Dr. Susumu Tonegawa in 1987, and Dr. Tasuku Honjo in 2018, three of these laureates—half of the total—were awarded in the field of immunology. This highlights immunology as a field in which Japan excels. We sincerely appreciate your continued support for the further advancement of immunology research in Japan, as well as for Dr. Sakaguchi’s ongoing work in this field.

In celebration of Dr. Sakaguchi’s Nobel Prize, The University of Osaka Foundation for the Future has established the “Sakaguchi Shimon Research Advancement Fund.” We ask for your support to enable Dr. Sakaguchi to continue and further advance his outstanding research.

For further details, please refer to the URL below.

https://www.miraikikin.osaka-u.ac.jp/en

Donations can be made via The University of Osaka Foundation for the Future website using a credit card, bank transfer, or other methods. If you wish to make a donation, please select “Support for Schools/Graduate Schools/Institutes and Facilities” as the purpose of your donation, then select “Sakaguchi Shimon Research Advancement Fund” as the designated fund.