The Nobel Prize for Physiology and Medicine of 2025 was awarded to Mary Brunkou, Fred Ramsdell and Shimon Sakaguchi “for discoveries regarding peripheral immune tolerance.”
Studies of scientists have shown that in the human immune system there are special cells-regulatory T cells that do not allow immunity to attack the body's own tissues. As the chairman of the Nobel Committee Olle Kemp explained, it was these discoveries that made it possible to understand why most people do not develop severe autoimmune diseases, such as type 1 diabetes or multiple sclerosis.
Back in 1995, one of the current Sakaguchi laureates made a breakthrough, proving that the immune system is more complicated than it was considered. Prior to this, scientists thought that protection against autoimmune reactions occurs only in the thymus gland, where dangerous cells were destroyed. Sakaguchi discovered a new type of cells that act as “guards” and do not allow immunity to attack their own fabrics.
In 2001, Brunkou and Ramsdell found out that mice with strong autoimmune reactions have a mutation in the FOXP3 gene. Later it turned out that in people similar mutations cause a rare, but severe disease – IPEX syndrome.
In 2003, Sakaguchi combined these discoveries and proved that it was the FoxP3 gene that controls the development of regulatory T cells, the very cells that it discovered earlier.
These studies changed the understanding of the immune system and discovered new treatment paths. Thanks to them, therapies are now being developed against autoimmune diseases and cancer, as well as methods that can make the organs more successful, said in the Nobel Committee. Some of these approaches are already undergoing clinical trials.
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Every year, the Nobel Prize laureates are chosen by the Norwegian Nobel Committee, the five members of which are appointed by the Norway Parliament. The names of the laureates are announced in October in Oslo.
