Answer: Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi
Notes: The 2025 Nobel Prize in Physiology or Medicine was awarded to Mary E. Brunkow, Fred Ramsdell, and Shimon Sakaguchi for discovering how the immune system decides what to attack or protect. The prize was announced on 6 October 2025 at the Nobel Assembly, Karolinska Institutet, Stockholm, Sweden. The research focuses on peripheral immune tolerance, which involves immune components outside the central nervous system (CNS). They identified regulatory T (Treg) cells, which prevent the immune system from attacking the body itself. Their work explained how autoimmune diseases develop and confirmed Treg cell function. Sakaguchi previously won the Canada Gairdner Award (2015) for the same discovery.
