Americans win Nobel prize in medicine for work on human immune system

A trio of scientists — two of them American and one Japanese — have won the Nobel Prize in Medicine for their discoveries concerning peripheral immune tolerance, a mechanism by which the body helps prevent itself from attacking its own tissues instead of foreign invaders.

Mary E. Brunkow, Fred Ramsdell and Shimon Sakaguchi will share the prize for discoveries that “launched the field of peripheral tolerance, spurring the development of medical treatments for cancer and autoimmune diseases,” the Nobel Assembly said in a news release. The trio will now share the prize money of 11 million Swedish kronor (nearly $1.2 million).

“This may also lead to more successful transplantations. Several of these treatments are now undergoing clinical trials,” it added.

Autoimmune diseases can be triggered when T cells, our body’s primary defense mechanism against harmful pathogens, malfunction.

Together, the trio’s discoveries lay a crucial foundation for understanding another way our immune system keeps itself in check, known as peripheral tolerance — a key to understanding why some people suffer from certain autoimmune diseases while others don’t.

To prevent damage, our body attempts to eliminate malfunctioning T cells in a lymphoid organ located in the chest, called the thymus, through a process known as central tolerance, according to the Associated Press.

The discovery began in 1995, when Sakaguchi, a distinguished professor at the Immunology Frontier Research Center at Osaka University in Japan, found a previously unknown class of immune cells that protect against autoimmune diseases.

Six years later, in 2001, Mary Brunkow, now a senior program manager at the Institute for Systems Biology in Seattle, along with Ramsdell, now a scientific adviser for Sonoma Biotherapeutics in San Francisco, discovered the specific genetic mutation that results in a severe autoimmune disease called IPEX.

They named this gene Foxp3.

In 2003, Sakaguchi was able to prove that it is, in fact, the Foxp3 gene that governs the development of the cells he had identified nearly a decade earlier. These cells are now known as regulatory T cells, and their job is to monitor other T cells and ensure they don’t go awry.