Shimon Sakaguchi, Specially Appointed Professor at Osaka University, to Receive 2025 Nobel Prize in Physiology or Medicine

It has been announced that Dr. Shimon Sakaguchi, Specially Appointed Professor at Osaka University, will be awarded the 2025 Nobel Prize in Physiology or Medicine. Professor Sakaguchi's long years of research led to the discovery of "regulatory T cells" (Tregs), a groundbreaking finding vital for understanding the fundamental principles of the immune system. This discovery is highly acclaimed for opening new avenues in the treatment of autoimmune diseases and allergic conditions.

Regulatory T cells are immune cells that act as a "brake" to suppress excessive immune responses in the body. Their function prevents immune cells from mistakenly attacking the body's own tissues, as seen in autoimmune diseases (e.g., Type 1 diabetes), and controls uncontrolled allergic reactions like hay fever and atopic dermatitis. Professor Sakaguchi began researching this immune suppressive mechanism in 1979 and clearly identified the existence of regulatory T cells in 1995. The demonstration that these regulatory T cells were the true identity of the previously conceptional "suppressor T cells" marked a significant turning point in the history of immunology.

This discovery has the potential to fundamentally change our understanding of the immune system's balance and our approach to various diseases caused by its dysregulation. Already, it is expected to lead to the development of new treatments for Type 1 diabetes and allergic diseases. Furthermore, controlling immune function through this knowledge is envisioned to contribute to a wide range of medical fields, including cancer therapy.

Following the announcement of the award, numerous messages of congratulations have flooded social media. In particular, many who learned about regulatory T cells through the popular manga "Cells at Work!" expressed surprise and joy, with comments such as "A discovery that rewrites textbooks came from a Japanese researcher!" and "The cell I learned about in Cells at Work! just won the Nobel Prize!" High attention has also come from government officials, with Prime Minister Ishiba reportedly calling Professor Sakaguchi directly to ask questions. There is significant national anticipation that this revolutionary achievement will bring great hope to the future of medicine.

The Context

For non-Japanese readers, understanding the significance of regulatory T cells (Tregs) is crucial. The immune system is designed to protect the body from foreign invaders like viruses and bacteria. However, sometimes it can become overactive or misdirected, leading to serious health issues. Autoimmune diseases occur when the immune system mistakenly attacks the body's own healthy cells and tissues, such as in Type 1 diabetes where insulin-producing cells are destroyed. Allergies, on the other hand, are an exaggerated immune response to harmless substances like pollen or certain foods.

Before Professor Sakaguchi's discovery, the concept of "suppressor T cells" existed, suggesting some cells could quiet down immune responses, but their exact nature remained elusive. Sakaguchi's definitive identification of Foxp3-expressing CD4+ regulatory T cells in 1995 provided the concrete evidence needed, fundamentally clarifying how the immune system maintains self-tolerance and prevents uncontrolled inflammation. This paved the way for targeted therapies that aim to either boost Treg function (for autoimmune diseases and allergies) or suppress it (in contexts like cancer where an overly suppressed immune response might allow tumors to grow).

The manga "Cells at Work!" (はたらく細胞, Hataraku Saibō) is an internationally popular educational series that anthropomorphizes various cells of the human body, depicting them as characters working within a living organism. It has been praised for making complex biological concepts accessible and engaging, particularly for younger audiences. The mention of regulatory T cells in the manga highlights how this scientific concept has permeated popular culture in Japan, making the Nobel recognition resonate even more deeply with the public who were already familiar with the "brake" cells through entertainment.