astronomy

Shimon Sakaguchi

Shimon Sakaguchi is a astronomy topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Shimon Sakaguchi rather than just read about it. In short: Shimon Sakaguchi (坂口志文, Sakaguchi Shimon; born 19 January 1951) is a Japanese immunologist. He is a distinguished professor at Osaka University and a professor emeritus at Kyoto University.

Key takeaways

Shimon Sakaguchi belongs to astronomy; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Shimon Sakaguchi to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Shimon Sakaguchi from memory before moving on to harder problems.

Reference excerpt

Shimon Sakaguchi (坂口志文, Sakaguchi Shimon; born 19 January 1951) is a Japanese immunologist. He is a distinguished professor at Osaka University and a professor emeritus at Kyoto University. His work includes the discovery of regulatory T cells and describing their role in the immune system. In 2025, he was jointly awarded the Nobel Prize in Physiology or Medicine with Mary E. Brunkow and Fred Ramsdell.

Early life and education Shimon Sakaguchi was born on 19 January 1951 in Nagahama, Shiga. He received a medical degree in 1976 from the Faculty of Medicine at Kyoto University. In 1982, he also received a PhD degree from Kyoto University.

Career Sakaguchi undertook postdoctoral research in the United States at Johns Hopkins University and Stanford University from 1983 to 1987 as a Lucille P. Markey Scholar. Later, he worked as an assistant professor in the Department of Immunology at the Scripps Research Institute. After returning to Japan in 1991, he worked at Riken as an investigator of the Japan Science and Technology Agency. Later, he became the head of the Department of Immunopathology at the Tokyo Metropolitan Institute of Gerontology. Between 1998 and 2011, he worked as a professor and chairman of the Department of Experimental Pathology at the Institute for Frontier Medical Sciences of Kyoto University. From 2007 to 2011, he also served as the institute's director. His lab was moved to Osaka University in 2011.

Research

In a 1995 study, Sakaguchi and his colleagues showed the existence of regulatory T cells, a previously unknown subset of T cells expressing CD4 and CD25 that modulate the immune system and help maintain immune tolerance. They injected BALB/c athymic mice with a suspension of CD4+ cells previously depleted of CD25+ cells and found that the mice subsequently developed autoimmune diseases (e.g. thyroiditis and gastritis). However, reconstitution of CD4+CD25+ cells shortly after the initial injection of CD4+CD25− cells prevented the development of autoimmunity. In 2003, Sakaguchi's group demonstrated the importance of FOXP3 in the development and function of regulatory T cells.

Honours and awards

On 6 October 2025, Sakaguchi was awarded the Nobel Prize in Physiology or Medicine with Mary E. Brunkow and Fred Ramsdell "for their discoveries concerning peripheral immune tolerance."

2004: William B. Coley Award (with Ethan M. Shevach) 2008: Keio Medical Science Prize (with Fred Gage) 2009: Medal of Honor with Purple Ribbon (Japan) 2011: Asahi Prize 2012: Foreign associate of the National Academy of Sciences 2015: Chunichi Culture Award 2015: Canada Gairdner International Award 2016, 2018, 2021: Asian Scientist 100, Asian Scientist 2015: Clarivate Citation laureates in Physiology or Medicine (with Shevach and Alexander Rudensky) 2017: Crafoord Prize (with Ramsdell and Rudensky) 2017: Person of Cultural Merit (Japan) 2017: Momofuku Ando Prize 2019: Order of Culture (Japan) 2020: Paul Ehrlich and Ludwig Darmstaedter Prize 2020: Robert Koch Prize 2023: Debrecen Award for Molecular Medicine 2025: Nobel Prize in Physiology or Medicine (with Brunkow and Ramsdell)

References

External links

Osaka University Immunology Frontier Research Center. Shimon Sakaguchi on Nobelprize.org

Illustrations

Worked examples

Example 1 — a first encounter with Shimon Sakaguchi

Start with the simplest possible case. Write down what Shimon Sakaguchi claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In astronomy, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Shimon Sakaguchi before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Shimon Sakaguchi ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Shimon Sakaguchi

In research: Shimon Sakaguchi appears in astronomy research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Shimon Sakaguchi in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Shimon Sakaguchi is common in secondary-school and first-year university syllabi. It links to neighbouring topics 1951 births, Academic staff of the University of Osaka, International members of the National Academy of Sciences, so understanding it makes those chapters shorter.
In everyday life: Look for Shimon Sakaguchi outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Shimon Sakaguchi in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Shimon Sakaguchi means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Shimon Sakaguchi out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Shimon Sakaguchi in simple terms?

Shimon Sakaguchi (坂口志文, Sakaguchi Shimon; born 19 January 1951) is a Japanese immunologist. He is a distinguished professor at Osaka University and a professor emeritus at Kyoto University.

Why does Shimon Sakaguchi matter?

Because it connects several astronomy ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Shimon Sakaguchi?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Shimon Sakaguchi.