Medicine 2025 · Announced Oct 6
Shimon Sakaguchi
The immunologist who found the immune system's guard cells.
Born 1951 · Japan · Osaka University
30 yrs
The wait, from Sakaguchi's guard-cell paper (1995) to the prize
1951
Year born
3
People sharing this prize
Oct 6
Announced in 2025
Their part in the prize
Your immune system kills germs. Something has to stop it from killing you too. Sakaguchi found a kind of guard cell, the regulatory T cell. Brunkow and Ramsdell found the gene, FOXP3, that those guards need.
Why it matters
When the guards fail, the body attacks itself. That is what happens in diseases like type 1 diabetes. Doctors are now testing ways to boost the guards, or to turn them down to fight cancer.
The road to the prize
- 1995Sakaguchi describes regulatory T cells.
- 2001Brunkow and Ramsdell trace a mouse autoimmune disease to the FOXP3 gene.
- 2003FOXP3 is shown to be the master switch of the guard cells.
- 2025Nobel Prize in Physiology or Medicine.
Shared with
The official reason for all 3: "for their discoveries concerning peripheral immune tolerance"