US and Japanese researchers win 2025 Nobel Prize in medicine

The 2025 Nobel Prize in Physiology or Medicine has been awarded to three scientists: Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi. Their pioneering work focused on how the immune system avoids attacking the body’s own tissues, an issue central to many diseases. The Nobel Assembly at the Karolinska Institute in Stockholm announced the winners today, bringing lasting recognition to their contributions, according to Euronews.

Brunkow and Ramsdell work in the United States, while Sakaguchi is based in Japan. Together, they revealed mechanisms behind peripheral immune tolerance. This biological process prevents autoimmune reactions that can be harmful. Citing the impact as «groundbreaking,» the Assembly stated that the trio’s work has significantly deepened the scientific understanding of immune regulation and opened new avenues for treating autoimmune diseases.

The Prize in Physiology or Medicine has honored 229 laureates since its inception in 1901. Last year, the Assembly recognized Victor Ambros and Gary Ruvkun, who were honored for their discovery of microRNA, a molecule that acts as a molecular switch controlling cellular activity.

This week’s Nobel announcements will continue with physics, chemistry and literature. The Nobel Peace Prize will be announced on Friday, followed by the Nobel Memorial Prize in Economic Sciences on Monday. All laureates will formally receive their awards on Dec. 10, which marks the anniversary of Alfred Nobel’s death. The Swedish inventor and industrialist created the prizes in his will. He died in 1896.