The 2025 Nobel Prize in Physiology or Medicine has been jointly awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their pioneering discoveries on peripheral immune tolerance — specifically focusing on the role of regulatory T cells (Tregs) and the FOXP3 (Forkhead Box Protein P3) gene in maintaining immune balance.
Announced by: Nobel Assembly at the Karolinska Institutet, Stockholm, Sweden.
Field: Physiology or Medicine
Core Discovery: Mechanisms that help the immune system differentiate between harmful invaders and the body’s own cells.
Nobel-Winning Discovery
Theme: Peripheral Immune Tolerance
The research uncovers how Regulatory T Cells (Tregs) prevent the immune system from mistakenly attacking the body’s own tissues — a process known as autoimmunity.
- Peripheral immune tolerance: The mechanism by which immune responses against self-antigens are suppressed in tissues outside the thymus and bone marrow.
- Tregs (Regulatory T Cells) act as “immune system peacekeepers,” ensuring self-tolerance and preventing autoimmune diseases.
- FOXP3 gene: A master regulator that controls the development and function of Tregs.
About the Laureates
Shimon Sakaguchi (Japan)
- Nationality: Japanese
- Position: Professor, Osaka University, Japan
- Field: Immunology
- Key Discovery:
- First identified Regulatory T Cells (Tregs) in 1995.
- Showed their critical role in preventing autoimmunity by suppressing overactive immune responses.
- His research proved that immune tolerance failure leads to autoimmune diseases.
- Earlier Awards:
- Canada Gairdner Award (2015) for the same discovery.
- Former Lucille P. Markey Scholar (USA).
- Education: Doctor of Medicine (Kyoto University, 1983).
Mary E. Brunkow (USA)
- Qualification: Ph.D. in Molecular Biology, Princeton University.
- Position: Senior Program Manager, Institute for Systems Biology, Seattle.
- Contribution:
- Studied mutations in scurfy mice, leading to autoimmune symptoms.
- In 2001, co-discovered that mutations in the FOXP3 gene caused severe autoimmune disorders (IPEX syndrome) in humans.
Fred Ramsdell (USA)
- Qualification: Ph.D. in Immunology, University of California, Los Angeles (UCLA).
- Position: Scientific Advisor, Sonoma Biotherapeutics, Washington.
- Contribution:
- Along with Brunkow, identified the link between FOXP3 gene mutations and immune dysfunctions.
- Demonstrated how FOXP3 controls Treg development, confirming Sakaguchi’s earlier hypothesis.
Scientific Significance of Their Discoveries
| Field | Impact |
| Autoimmune Diseases | Enhancing Tregs could help prevent diseases like Type 1 Diabetes, Rheumatoid Arthritis, Multiple Sclerosis. |
| Cancer Therapy | Suppressing Tregs around tumors could make immune therapies more effective against cancer cells. |
| Transplantation Medicine | Better Treg regulation can reduce organ transplant rejection rates. |
About Human Immune System
Function:
The immune system defends the body against harmful pathogens (bacteria, viruses, fungi, parasites) and abnormal cells (like cancer).
Types of Immunity:
- Innate Immunity (Non-Specific):
Immediate defense via physical barriers (skin, mucosa), macrophages, and inflammation. - Adaptive Immunity (Specific):
Specialized defense via T-cells (cell-mediated immunity) and B-cells (antibody production).
Immune Tolerance Mechanisms:
- Central Tolerance:
Occurs in thymus/bone marrow; self-reactive cells are eliminated. - Peripheral Tolerance:
Occurs in body tissues; Tregs suppress any remaining self-reactive cells.
Regulatory T Cells (Tregs)– Maintain balance between immune activation and suppression, preventing the body from attacking itself.
India and Nobel Prize in Medicine
- Har Gobind Khorana (1968) — Only Indian-born Nobel laureate in Medicine.
- Awarded with: Marshall Nirenberg and Robert Holley (USA).
- Contribution: Decoded the genetic code and its role in protein synthesis.
- Khorana’s work forms the basis of molecular genetics and biotechnology research today.
About Nobel Prize
| Particulars | Details |
| Founded by | Alfred Nobel (Swedish inventor of dynamite) |
| First Awarded | 1901 |
| Fields | Physics, Chemistry, Medicine, Literature, Peace (Economics added in 1968) |
| Awarded in | Stockholm, Sweden (except Peace Prize — awarded in Oslo, Norway) |
| Maximum Laureates per Prize | Up to 3 individuals |
| Components | Gold medal, diploma, and cash award |
| First Woman Laureate | Marie Curie (won twice — Physics 1903, Chemistry 1911) |
Nobel Prize and India
| Field | Indian Laureate | Year | Contribution |
| Literature | Rabindranath Tagore | 1913 | Gitanjali |
| Physics | C.V. Raman | 1930 | Discovery of Raman Effect |
| Physiology/Medicine | Har Gobind Khorana | 1968 | Genetic code and protein synthesis |
| Peace | Mother Teresa | 1979 | Humanitarian work |
| Economics | Amartya Sen | 1998 | Welfare economics |
| Peace | Kailash Satyarthi | 2014 | Child rights activism |