Nobel Prize Winners 2025: Two US Immunologists Win Science’s Top Honor

Oct 6, 2025, 07:12 EDT

Nobel Prize Winners 2025: US scientists Mary E. Brunkow and Fred Ramsdell were awarded the Medicine Prize today for discovering peripheral immune tolerance. Their groundbreaking work on the Foxp3 gene and regulatory T cells protects the body from autoimmune diseases, paving the way for new cancer treatments.

Nobel Prize Winners 2025 in Science
Nobel Prize Winners 2025 in Science

Nobel Prize Winners 2025: The Nobel Prize is one of the few scientific announcements that really gets people's attention. The winners for 2025 were announced today. Mary E. Brunkow and Fred Ramsdell, two brilliant minds from the United States, are sharing the prestigious Medicine prize. Their joint study of peripheral immune tolerance is a game-changer that shows us the immune system's hidden "security guards." This discovery changes the way we think about and treat severe autoimmune diseases and cancer right away, showing that American creativity continues to push medical progress around the world.

Which Americans are Nobel Prize Winners for Science in 2025? 

Two American immunologists, known for their important genetic discoveries, were honored the Nobel Prize 2025 with their Japanese colleague. Here is a quick look at the US scientists:

Mary E. Brunkow, Ph.D.

A graduate of Princeton University, Brunkow currently serves as a Senior Program Manager at the Institute for Systems Biology in Seattle, Washington. She conducted the foundational work in identifying the crucial regulatory gene.

Fred Ramsdell, Ph.D.

Ramsdell is a Scientific Advisor at Sonoma Biotherapeutics, based in San Francisco, California. He worked closely with Brunkow to uncover the specific role of the gene in regulating immune response.

The three of them share the award for finding the Foxp3 gene, which is the master switch for specialized immune cells. This is one of the most important self-regulating mechanisms in the immune system.

Peripheral Tolerance - The Discovery that Won the Nobel Prize 

The award honors a long-standing question in medicine: how does the immune system protect us from threats without harming our own organs?

Scientists knew that the immune system got rid of some harmful cells early on, a process known as central tolerance. This system, though, wasn't perfect.

Brunkow and Ramsdell showed that a mutated gene, which they named Foxp3, caused severe autoimmune diseases like IPEX syndrome. This mutation basically turned off the immune system's internal stop sign.

Their research helped show that there is a separate, active check-and-balance system called peripheral tolerance. This system depends on special immune cells called regulatory T cells, or "Tregs," which keep an eye on other cells. They actively keep the peace by stopping other immune cells from attacking the body's own tissues.

The findings are already underpinning dozens of new treatments in clinical trials, offering hope for millions affected by chronic illnesses and difficult-to-treat cancers.

Brunkow and Ramsdell will split the 11 million Swedish kronor prize, which will give them more than just immediate fame and prestige. It will also show how their work has had an effect on the world. Now that the focus has moved to the other categories—Physics, Chemistry, and Peace—American scientists are ready to take the lead again, continuing a long history of intellectual leadership.

Harshita Singh
Harshita Singh

Senior Content Writer

Harshita Singh specializes in US affairs and general knowledge, simplifying intricate geopolitical and historical subjects into clear, digestible insights for learners. Holding a BA (Hons) in English from the University of Delhi and with over three years of experience in educational writing, she produces authoritative, thoroughly researched content that empowers readers to engage confidently with global current affairs. For inquiries, you can reach out to her at harshita.singh@jagrannewmedia.com.
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