The 2025 Nobel Prize in Physiology or Medicine has been awarded jointly to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for their discoveries concerning peripheral immune tolerance, a breakthrough that has transformed understanding of how the immune system avoids attacking the body’s own tissues.
Their pioneering research uncovered the identity and genetic control of regulatory T cells, the so-called “security guards” of the immune system that prevent autoimmune attack.