Discoveries about how our immune systems avoid attacking our own bodies — research which helped create new pathways for treating autoimmune diseases — won the 2025 Nobel Prize for Physiology or Medicine.
T-cells are designed to attack proteins in pathogens, but those proteins are often similar to our body’s own proteins. Mary Brunkow, Fred Ramsdell, and Shimon Sakaguchi discovered that the immune system has “self-tolerance” safeguards which prevent it from attacking our own cells.
Crucially, the findings also helped create new cancer treatments: Cancer cells use the body’s self-tolerance to hide, and immunotherapy is designed to take the brakes off and allow the immune system to attack those cells.