The Nobel for FOXP3: When Biology Comes Full Circle

What happened

The 2025 Nobel Prize in Medicine has been awarded for one of the most fundamental discoveries in modern immunology: how the body prevents its own immune system from turning against itself.

In the 1990s, Shimon Sakaguchi discovered that a small subset of T cells — now known as regulatory T cells (Tregs), act as the “brakes” of the immune system, suppressing autoimmune responses. Around the same time, Mary Brunkow and Fred Ramsdell, working at Celltech (a UK biotech company, not a university lab), identified the gene FOXP3 as the master switch for these regulatory cells. Mutations in FOXP3 caused a devastating autoimmune condition in mice, and later in humans, known as IPEX syndrome.

Together, their work uncovered the genetic and cellular machinery that maintains immune tolerance (the reason our immune system doesn’t destroy our own tissues).

One striking detail: Brunkow and Ramsdell made their discovery while working in the biotech industry. It’s one of the few Nobel Prizes ever awarded directly to industrial scientists, not academics.

Why it matters

This isn’t just a prize about immunology history. It’s a recognition that immune balance is central to health.

Most of biotech’s big wins in the past decade have come from stimulating the immune system — checkpoint inhibitors, CAR-T cells, mRNA vaccines. The Treg–FOXP3 story highlights the opposite side of immunity: the mechanisms that keep activation in check. FOXP3 doesn’t suppress immunity broadly; it restores the body’s ability to regulate itself.

The importance of this pathway becomes clearest in a rare condition called IPEX syndrome, a genetic disorder where FOXP3 is missing or nonfunctional. Without FOXP3, people are born without regulatory T cells, the peacekeepers that normally stop the immune system from attacking its own tissues. The result is catastrophic: early, widespread autoimmunity that can destroy the gut, pancreas, and skin within months of birth.

Recently, researchers have begun using cell and gene therapies to restore FOXP3, essentially giving patients back their immune “peacekeepers.” For the first time, these therapies are re-establishing immune balance in humans who previously had none. It’s a striking demonstration of how a Nobel-winning discovery has already turned into real, living medicine.

And it’s also a win for biotech itself. The Nobel Committee explicitly credited discoveries made inside a company, at Celltech, signaling that foundational science can come from industry labs, not just academia.

The big picture

The science of immune tolerance has quietly become one ...