Stockholm: The 2025 Nobel Prize in Physiology or Medicine has been awarded to Mary Brunkow and Fred Ramsdell of the United States, along with Shimon Sakaguchi of Japan, for their groundbreaking research on peripheral immune tolerance, a mechanism that prevents the body’s immune system from attacking its own organs.
The laureates’ work revealed the role of regulatory T cells, often described as the immune system’s “security guards,” which monitor other immune cells and ensure that they do not target the body’s own tissues. Their discoveries have been pivotal in understanding why autoimmune diseases develop in some individuals while others remain unaffected.
Key Discoveries
- Shimon Sakaguchi (Japan) – In 1995, Sakaguchi discovered a previously unknown class of immune cells, now known as regulatory T cells, challenging the prevailing belief that immune tolerance was established solely in the thymus through central tolerance.
- Mary Brunkow and Fred Ramsdell (USA) – In 2001, they discovered that a mutation in the Foxp3 gene made certain mice highly susceptible to autoimmune diseases. They further showed that mutations in the human equivalent of this gene cause IPEX, a severe autoimmune condition.
- Sakaguchi (2003) – Linked these discoveries, demonstrating that Foxp3 controls the development of regulatory T cells, which prevent immune cells from attacking the body’s own tissues.
Impact and Applications
The laureates’ discoveries have opened up the field of peripheral immune tolerance, paving the way for medical treatments in:
- Autoimmune diseases – Understanding the mechanisms allows for targeted therapies to prevent self-directed immune attacks.
- Cancer treatment – Insights into regulatory T cells enable therapies that can enhance the immune system’s ability to target tumors.
- Organ transplantation – Their work informs strategies to prevent transplant rejection.
Many therapies based on these discoveries are currently in clinical trials, promising safer and more effective treatments for patients worldwide.
About the Nobel Laureates
- Mary E. Brunkow (USA) – Affiliated with the Institute for Systems Biology, Seattle, Washington. Born in 1961.
- Frederick J. Ramsdell (USA) – Affiliated with Sonoma Biotherapeutics, San Francisco, California. Born on December 4, 1960.
- Shimon Sakaguchi (Japan) – Affiliated with Osaka University, Osaka. Born on January 19, 1951.
Olle Kämpe, chair of the Nobel Committee, said:
“Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases.”
The 2025 Nobel Prize highlights the power of fundamental research in immunology, demonstrating how basic discoveries can translate into life-saving medical applications.
