Brunkow, Ramsdell & Sakaguchi Win 2025 Nobel in Medidine for Immune System Discovery
Pune, Oct 7, 2025 — In a landmark announcement that has resonated across global scientific and medical circles, the 2025 Nobel Prize in Physiology or Medicine has been jointly awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi. Their pioneering work sheds new light on how the human immune system prevents itself from turning against its own tissues — a mechanism known as peripheral immune tolerance.
(image courtesy: https://www.nobelprize.org/)
The Nobel Assembly at the Karolinska Institute in Stockholm recognized the laureates “for their discoveries concerning peripheral immune tolerance” — in particular, their work elucidating how regulatory T cells (often called T-regs) act as gatekeepers, preventing autoimmune reactions.
Sakaguchi’s early research first identified these regulatory T cells in the mid-1990s, while Brunkow and Ramsdell later uncovered the critical role of the FOXP3 gene in controlling their formation and function. Mutations in FOXP3 are linked to severe autoimmune disorders in mice and humans.
By clarifying how immune responses are held in check, their discoveries open pathways toward new therapies for autoimmune diseases, improving organ transplant acceptance, and even refining cancer treatments that manipulate the immune system safely.
The laureates share a prize sum of 11 million Swedish kronor and will be honored formally in December.
This development marks a significant milestone in immunology. From Pune to Stockholm, scientists and medical professionals alike will be watching how these revelations translate into real-world therapies.
