Trio wins Nobel Prize in medicine

Three scientists won the Nobel Prize in medicine Monday for discoveries about how the immune system knows to attack germs and not our own bodies.

- By Kostya MANENKOV, LAURAN NEERGAARD AND LINDSEY WASSON

The work by Mary E. Brunkow, Fred Ramsdell and Dr. Shimon Sakaguchi uncovered a key pathway the body uses to keep the immune system in check, called peripheral immune tolerance. Experts called the findings crucial to understanding autoimmune diseases such as Type 1 diabetes, rheumatoid arthritis and lupus.

In separate projects over several years, the trio of scientists — two in the U.S. and one in Japan — identified the importance of what are now called regulatory T cells.

Scientists are currently using those findings in a variety of ways: to discover better treatments for autoimmune diseases, to improve organ transplant success and to enhance the body’s own fight against cancer, among others.

“Their discoveries have been decisive for our understanding of how the immune system functions and why we do not all develop serious autoimmune diseases,” said Olle Kampe, chair of the Nobel Committee.

Brunkow, 64, is now a senior program manager at the Institute for Systems Biology in Seattle. Ramsdell, 64, is a scientific advisor for San Francisco-based Sonoma Biotherapeutics. Sakaguchi, 74, is a distinguished professor at the Immunology Frontier Research Center at Osaka University in Japan.

The award, officially known as the Nobel Prize in Physiology or Medicine, is the first of the 2025 Nobel Prize announcements and was announced by a panel at the Karolinska Institute in Stockholm.

The work that led to the coveted award

The immune system has overlapping ways to detect and fight bacteria, viruses and other intruders. But sometimes certain immune cells run amok, mistakenly attacking people's own cells and tissues to cause autoimmune diseases.