Triumph in Immune Tolerance: Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi Awarded the 2025 Nobel Prize in Physiology or Medicine

On October 6, 2025, the Nobel Assembly at Karolinska Institutet announced the 2025 Nobel Prize in Physiology or Medicine, awarding it jointly to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi. This prestigious honor recognizes their groundbreaking discoveries concerning peripheral immune tolerance, a crucial mechanism that prevents the immune system from attacking the body's own tissues.

Shimon Sakaguchi is renowned for his identification of a new class of T cells known as regulatory T cells (Tregs). These cells are characterized by the presence of the CD4 and CD25 proteins on their surface and play a pivotal role in calming the immune system, thereby preventing autoimmune diseases. Sakaguchi's work, which began in the early 1990s, was initially met with skepticism, but it has been pivotal in understanding how the immune system is regulated.

Mary E. Brunkow and Fred Ramsdell have significantly contributed to this field by providing additional evidence that supports Sakaguchi's discovery. Brunkow's work, conducted at Celtech biotechnology in Washington, demonstrated the importance of immune tolerance in preventing autoimmune diseases. Ramsdell's contributions have also been instrumental in understanding the role of these regulatory cells.

This award highlights the importance of peripheral immune tolerance in maintaining health and preventing autoimmune diseases. The research by these laureates has opened new avenues for developing treatments and therapies for conditions where the immune system malfunctions.

The Nobel Prize in Physiology or Medicine is one of the most esteemed awards in the scientific community, and this year's selection underscores the significance of immune tolerance in medicine.

For more information, visit the official Nobel Prize website at NobelPrize.org, which provides detailed insights into the research conducted by the laureates.

This year's award is a testament to the power of scientific collaboration and dedication to advancing our understanding of the human body.

As the scientific community continues to explore the intricacies of immune tolerance, these discoveries will undoubtedly pave the way for novel therapeutic approaches and a better understanding of the immune system's role in health and disease.

With this recognition, the work of Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi stands as a beacon of innovation and progress in the field of medicine.

Stay tuned for more updates and insights into the groundbreaking research that has earned them this prestigious honor.

For further details, including an announcement video and background information, visit the Nobel Prize YouTube channel or the official Nobel Prize website.