Nobel Prize in Physiology or Medicine 2025

The 2025 Nobel Prize in Physiology or Medicine was awarded for their groundbreaking discoveries concerning peripheral immune tolerance that prevents the immune system from harming the body.
Shimon Sakaguchi (Japan) received the award for discovering regulatory T-cells.
Mary E. Brunkow and Fred Ramsdell (USA) were honoured for identifying the Foxp3 gene, which controls immune regulation.

About Nobel Prize in Physiology or Medicine

The Nobel Prize in Physiology or Medicine is awarded by the Nobel Assembly at the Karolinska Institute in Stockholm, Sweden, for outstanding contributions to medical research.
First Laureate: In 1901, Emil von Behring received it for developing serum therapy to treat diphtheria.
Indian–Origin Laureate: In 1968, Har Gobind Khorana became the first Indian winner for decoding the genetic code guiding protein synthesis.

Scientists previously believed that the immune system prevented self-damage solely through central tolerance, which occurs in the thymus and bone marrow.
Some self-reactive T cells that escape central tolerance are restrained in peripheral tissues (e.g., lymph nodes, spleen). This stops them from mistakenly attacking healthy tissue.
Shimon Sakaguchi‘s pioneering work (in the mid-1990s) challenged prevailing views by demonstrating the existence of a subtype of T-cells called regulatory T-cells (Tregs) that identify and suppress these escaped self-reactive T-cells.
Mary Brunkow and Fred Ramsdell further advanced the field by identifying the FOXP3 gene. They showed that mutations in the FOXP3 gene disable regulatory T-cells, causing uncontrolled immune activation and loss of self-tolerance.
Together, their work elucidated how regulatory T cells enforce peripheral immune tolerance, thereby protecting the body from autoimmune damage while still allowing immune responses to pathogens.
Therapeutic Value: Insights into regulatory T-cells can guide new treatments for autoimmune diseases, organ transplants, and cancer immunotherapy.

Nobel Prize is a set of prestigious international awards given annually for outstanding achievements.
It was established by the will of Swedish inventor Alfred Nobel (the inventor of dynamite).
The Nobel Prizes were first awarded in 1901.
Categories: Prizes are awarded in six fields: Physics, Chemistry, Physiology or Medicine, Literature, Peace, and Economic Sciences.
- The Prize in Economic Sciences was introduced later in 1968 by the Sveriges Riksbank (Swedish central bank)