The research on immune system peacemakers was honored with the 2025 Nobel Prize in Physiology or Medicine.
Regulatory T cells, known as T-regs, serve as vital peacemakers for the immune system by calming it down after combating infections or healing injuries. These specialized T cells are crucial in preventing the immune system from attacking the body’s own tissues. If they fail, it can lead to autoimmune diseases or harmful inflammation. They also play a significant role in preventing the rejection of a fetus during pregnancy.
Shimon Sakaguchi of Osaka University in Japan first identified these essential cells in 1995. For this groundbreaking work, Sakaguchi shares the prize, valued at 11 million Swedish krona (over $1.1 million), with Mary Brunkow from the Institute for Systems Biology in Seattle and Fred Ramsdell, a cofounder of Sonoma Biotherapeutics, which operates in both San Francisco and Seattle. The Nobel Assembly at the Karolinska Institute in Stockholm announced the winners on October 6.
While at Celltech Chiroscience in Bothell, Washington, during the 1990s, Brunkow and Ramsdell discovered a mutation linked to a lethal autoimmune condition affecting male mouse pups. They pinpointed the mutation to a defect in a gene called FOXP3. This gene is crucial for the development of T-regs, as later revealed by Sakaguchi. Without sufficient T-regs, the immune system can unleash harmful reactions. Mutations in FOXP3 also lead to an autoimmune disorder known as IPEX in humans, a breakthrough highlighted by the American researchers in 2001.
Researchers are actively exploring ways to utilize T-regs to avoid the rejection of organ transplants and to address autoimmune diseases, food allergies, cancer, and other conditions where the immune system is hyperactive or misdirected.
