Message of congratulations to Professor Sakaguchi

I would like to offer Professor Shimon Sakaguchi my sincere congratulations for being awarded the Nobel Prize in Physiology or Medicine this year, together with Mary E. Brunkow and Fred Ramsdell.

I would like to express my deepest respect and congratulations for the more than four decades he dedicated to research on the mechanisms maintaining immune tolerance, and particularly his world-renowned achievements in discovering regulatory T cells (Treg) and elucidating their molecular basis, and am tremendously pleased that this work has been honored with this great distinction.

In the early 1980s, Professor Sakaguchi conceived the existence of a population of lymphocytes involved in suppressing the onset of autoimmune diseases and accumulated experimental evidence to prove this. From the 1990s onward, he obtained clear evidence that CD25⁺ CD4⁺ T cells are regulatory T cells which suppress the immune response, and he elucidated the molecular mechanisms—including the transcription factor Foxp3—essential for their differentiation and maintenance. These discoveries laid the foundation for a broad range of medical research, in areas such as autoimmune disorders, allergies, and cancer immunity, bringing about a paradigm shift in understanding immune homeostasis.

Professor Sakaguchi previously held a position at the RIKEN Research Center for Allergy and Immunology (now the RIKEN Center for Integrative Medical Sciences), and during his term there he consistently and earnestly pursued fundamental science. His unwavering research ethos resonates deeply with RIKEN's founding principle of creatively advancing science, and has provided great inspiration for our researchers.

I sincerely hope that this award will serve as an opportunity for society to reaffirm the importance of basic research. I extend my heartfelt wishes for Professor Sakaguchi's continued good health and outstanding achievements.