The laureates discovered the defenders of the immune system – regulatory T cells, which prevent immune cells from attacking our own bodies.

The discoveries of the Nobel laureates launched the field of peripheral tolerance, stimulating the development of medicine.
The Nobel Committee announced the laureates of the annual Prize in Medicine and Physiology on Monday, October 6. They were scientists Mary Brunkow, Fred Ramsdell and Shimon Sakakuchi. This was reported by the press service of the Nobel Foundation.

Three scientists won the Nobel Prize in Physiology or Medicine 2025 for their revolutionary discoveries in the field of peripheral immune tolerance, which prevents the damage that the immune system can cause to the body.

The laureates discovered the defenders of the immune system – regulatory T cells, which prevent immune cells from attacking our own bodies.

“Their discoveries were crucial to our understanding of how the immune system works and why not all of us get serious autoimmune diseases,” said Nobel Committee Chair Olle Kempe.

Shimon Sakaguchi made the first key discovery in 1995. He showed that the immune system is more complex and discovered a previously unknown class of immune cells that protect the body from autoimmune diseases.

Mary Brankov and Fred Ramsdell made a second important discovery in 2001 when they presented an explanation for why a certain strain of mice was particularly vulnerable to autoimmune diseases. The fact is that the mice have a mutation in a gene they called Foxp3.

They also showed that mutations in the human equivalent of this gene cause a serious autoimmune disease, IPEX.

Two years later, Shimon Sakaguchi was able to link these discoveries. He demonstrated that the Foxp3 gene controls the development of cells he identified in 1995. These cells, now known as regulatory T cells, control other immune cells and ensure that our immune system tolerates our own tissues.

The laureates’ discoveries launched the field of peripheral tolerance, spurring the development of medical treatments for cancer and autoimmune diseases. It will also contribute to more successful transplants.

Some of these treatments are now undergoing clinical trials.

Mary E. Brankov is an American molecular biologist and immunologist.

Fred Ramsdell is an American immunologist and vice president of research at the Parker Institute for Cancer Immunotherapy.

Shimon Sakaguchi is a Japanese scientist, professor at Kyoto University, and one of the leading experts on regulatory T cells and the mechanisms of immune tolerance.

As a reminder, French President Emmanuel Macron said that if US President Donald Trump wants to win the Nobel Peace Prize, he must influence Israel and stop the fighting in Gaza.