Regulatory T cells were identified by Shimon Sakaguchi in 1995, revealing a specialized immune cell population responsible for maintaining peripheral immune tolerance. His investigation into these cells changed the understanding of how the body modulates its immune response and prevents the onset of autoimmune disorders, eventually leading to his recognition with the Nobel Prize in Physiology or Medicine in 2025.
Education and Early Career
Born in Nagahama in 1951, Shimon Sakaguchi attended Shiga Prefectural Nagahama Kita High School before entering Kyoto University. He earned a medical degree in 1976, followed by a PhD from the same institution in 1982. During the mid-1980s, he conducted postdoctoral research in the United States at Johns Hopkins University and Stanford University as a Lucille P. Markey Scholar. He also served as an assistant professor at the Scripps Research Institute.
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Upon returning to Japan in 1991, Sakaguchi continued his research into pathology and immunology while working with the Japan Science and Technology Agency at Riken. In a 1995 study, he identified a subset of CD4+ T cells expressing CD25, which were essential for preventing autoimmune diseases. By injecting mice depleted of these cells, he demonstrated the onset of conditions such as gastritis and thyroiditis, proving that reintroducing these specific cells could successfully inhibit autoimmunity. In 2003, his research team further established the critical role of the FOXP3 gene in the development and functional stability of these regulatory cells.
Institutional Appointments
Sakaguchi served as the head of the Department of Immunopathology at the Tokyo Metropolitan Institute of Gerontology before joining the faculty at Kyoto University. From 1998 to 2011, he acted as a professor and chairman of the Department of Experimental Pathology at the Institute for Frontier Medical Sciences, serving as the institute's director from 2007 to 2011. In 2011, he moved his laboratory to Osaka University, where he continues to hold a distinguished professorship.
International Recognition
His research has been acknowledged by several major scientific institutions. He received the William B. Coley Award in 2004 and the Keio Medical Science Prize in 2008. His later honors include the Canada Gairdner International Award in 2015, the Crafoord Prize in 2017, and both the Robert Koch Prize and the Paul Ehrlich and Ludwig Darmstaedter Prize in 2020. In 2025, he was jointly awarded the Nobel Prize in Physiology or Medicine alongside Mary E. Brunkow and Fred Ramsdell for his contributions to the field of immune tolerance.
Fast facts
- Born: 19 January 1951, Nagahama, Japan
- Education: Kyoto University
- Field: Immunology and Pathology
- Key Discovery: Regulatory T cells
- 2025 Nobel Prize: Physiology or Medicine
- 2017 Award: Crafoord Prize
- Current Institution: Osaka University
- Membership: National Academy of Sciences
Questions readers ask
What is the function of regulatory T cells?
They modulate the immune system and help maintain immune tolerance, preventing the development of autoimmune diseases.
What role does FOXP3 play in Sakaguchi's research?
In 2003, Sakaguchi demonstrated that the FOXP3 gene is critical for the development and function of regulatory T cells.
Achievements
- Nobel Prize in Physiology or Medicine — 2025
- Crafoord Prize — 2017
- Held posts at Kyoto University and University of Osaka
- Educated at Kyoto University and Shiga Prefectural Nagahama Kita High School
- Fields of research: immunology and pathology
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