Nobel Prize in Medicine 2025 Honors Discoverers of the “Immune Checkpoint”
The 2025 Nobel Prize in Medicine has been awarded to researchers Mari E. Brunker and Fred Ramsdell from the United States, along with Japanese scientist Shimon Sakaguchi, in recognition of their research that uncovered how the body regulates its immune system to prevent attacks on its own tissues while maintaining the ability to combat microbes.
In its statement, the Nobel Committee highlighted that the prize is granted for “their discoveries regarding peripheral immune tolerance,” asserting that these findings have opened new horizons in understanding the balance of immune response. Professor Marie Vaherin-Herlinus from the Karolinska Institute explained that the award highlights the mechanisms that enable the body to fight external threats while avoiding the dangers of autoimmune diseases.
The committee further emphasized that a robust immune system must be regulated; otherwise, the risk of it attacking the body’s organs increases. In this context, the laureates discovered a type of regulatory T cells (also known as suppressor cells) that act as guards: they suppress the excessive activity of immune cells and prevent them from attacking healthy body tissues.
Additionally, the committee noted that these discoveries not only provided a new biological explanation but also established a wide research field and contributed to advancing efforts in developing new drugs and treatments, including therapies related to cancer and autoimmune diseases.
