Nobel Prize: Researcher Honored for Solving Fundamental Mystery of Immunity

Editorial

15:00 JST, October 7, 2025

It is a magnificent achievement in the field of immunology research, a source of pride for Japan. We would like to commend them for persevering through headwinds, staying true to their convictions and achieving significant results.

The Nobel Prize in Physiology or Medicine has been awarded to three researchers, including Shimon Sakaguchi, a specially appointed professor at the University of Osaka. A body is sometimes mistakenly harmed by its own immune system, and the award recognizes their groundbreaking discoveries regarding the mechanism that prevents the immune system from doing such harm.

T cells, a type of immune cell, are produced in the thymus. While their role is to protect the body from “enemies” like bacteria and viruses, they can sometimes mistakenly attack the body itself, causing autoimmune diseases such as rheumatism and type 1 diabetes.

In 1995, based on the idea that there must be cells capable of suppressing rogue T cells, Sakaguchi discovered “regulatory T cells (Treg cells),” which put the brakes on such T cells.

It can be said that his achievement of pioneering a new field, by independently elucidating a fundamental principle of immunity, has become highly regarded.

However, at the time of his discovery, the academic community was largely skeptical of this seemingly self-contradictory entity — immune cells that suppresses immune function.

Nevertheless, Sakaguchi, whose conviction deepened through repeated experiments, endured his solitude and advanced his research. We would like to express our respect for his single-minded pursuit of fundamental questions, driven by unshakable conviction.

Future applications in drug development are called for. Reducing Treg cells around cancer cells could pave the way for new treatments that stimulate attacks on cancer cells.

In contrast to the University of Tokyo and Kyoto University, which have produced numerous Nobel laureates, the University of Osaka has had little connection with the Nobel Prize. The joy of people at the university must be great.

This marks the second consecutive year of good news for Japan in the Nobel Prizes, following last year’s Peace Prize awarded to Nihon Hidankyo, formally known as the Japan Confederation of A- and H-Bomb Sufferers Organizations.

Combined with the Nobel Prize in Chemistry and the Nobel Prize in Physics, this is the first time in four years — since Syukuro Manabe’s winning of the prize in 2021 — that Japan has won one of the three natural science prizes. Including Manabe, who holds U.S. citizenship, this brings the total number of Japan-born laureates in the three natural science prizes to 26 people.

However, it is not uncommon for decades to pass between a discovery and the awarding of a Nobel Prize. Recently, Japan’s declining research capabilities have been pointed out. This state of affairs makes it uncertain whether Japan will maintain its pace of winning Nobel Prizes.

This situation comes partly from reduced university research funding and an increase in researchers working under unstable, fixed-term employment contracts. The number of students advancing to doctoral programs is also declining.

The government must strive to improve the research environment, by supporting young researchers’ freedom to pursue their work, to ensure that the seeds of future Nobel Prizes are not lost.

(From The Yomiuri Shimbun, Oct. 7, 2025)