Nobel Prize in Medicine 2025 goes to Mary E Brunkow, Fred Ramsdell, Shimon Sakaguchi

The Nobel Assembly Karolinska Institute, a medical university in Sweden, has announced the winners of the Nobel Prize 2025 for physiology or medicine. Mary E Brunkow, Fred Ramsdell, and Shimon Sakaguchi have received the award for their discoveries regarding peripheral immune tolerance.

“The 2025 medicine laureates have discovered how the immune system is kept in check. The body’s powerful immune system must be regulated, or it may attack our own organs. This year’s laureates identified the immune system’s security guards, regulatory T cells, which prevent immune cells from attacking our own body,” said the Nobel Prize page in a post on X.

“The 2025 Nobel Prize laureates’ discoveries launched the field of peripheral tolerance, spurring the development of medical treatments for cancer and autoimmune diseases. This may also lead to more successful transplantations. Several of these treatments are now undergoing clinical trials,” it added.

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Discoveries in medicine

Sakaguchi from Japan’s Osaka University discovered a new class of T cells. While swimming against the tide in 1995, he made a major discovery. Many researchers were, back then, convinced that immune tolerance only developed when potentially harmful immune cells were eliminated in the thymus, through a process called central tolerance. The scientist showed that the immune system is more complex and discovered a formerly unknown class of immune cells, which protect the body from autoimmune diseases.

On the other hand, Americans Brunkow and Ramsdell made a key discovery in 2001, that the mice have a mutation in a gene that they named Foxp3. They also showed that mutations in the human equivalent of this gene cause a serious autoimmune disease, IPEX.