Shimon Sakaguchi, Mary E. Brunkow, and Fred Ramsdell receive the Nobel Prize in Medicine

The Nobel Prize Award-giving organization announced that Mary Brunkow, Fred Ramsdell, and Shimon Sakaguchi, three scientists, had won the 2025 Nobel Prize in Physiology or Medicine for "their discoveries concerning peripheral immune tolerance" on Monday. A panel from the Karolinska Institute in Stockholm announced the first of six honors, the Nobel Prize in Medicine. The body uses peripheral immunological tolerance to prevent the immune system from targeting its own tissues rather than those of external invaders.

In a statement released on Monday, the Nobel Prize committee said, "Their discoveries have laid the foundation for a new field of research and spurred the development of new treatments, for example for cancer and autoimmune diseases." Between 1901 and 2024, 229 Nobel Prize laureates received the medical Nobel Prize 115 times.

Victor Ambros and Gary Ruvkun, both Americans, shared the prize last year for discovering microRNA. Outstanding accomplishments in literature, chemistry, physics, and peace are recognized with the annual prizes. Instant fame and a prize of almost 1.2 million dollars are included in the award.