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Tasuku Honjo

Research Fields

Molecular Immunology

Research Overview

Honjo is well known for his discovery of activation-induced cytidine deaminase (AID) that is essential for class switch recombination and somatic hypermutation. He has established the basic conceptual framework of class switch recombination starting from discovery of DNA deletion (1978). Dr. Honjo identified a series of key molecules involved in immune regulation, including IL-4, IL-5, SDF-1, and IL-2R αchain. Also appreciated is his seminal contribution to developmental biology by identification of RBP-J as the Notch signaling target. In addition, he discovered PD-1 (program cell death 1), a negative coreceptor at the effector phase of immune response and demonstrated that PD-1 inhibition contributes to cancer treatments. Anti-PD-1 cancer immunotherapy has been approved in US, EU, and Japan. This treatment revolutionalized the cancer therapy and is considered to be equivalent to penicillin in infectious diseases.


1966 M.D., Kyoto University
1975 Ph.D., Kyoto University
1971–1973 Fellow of Carnegie Institution of Washington, Department of Embryology
1973–1974 Visiting Fellow and Associate of National Institute of Child Health and Human Development, NIH
1974–1979 Assistant Professor of Faculty of Medicine, The University of Tokyo
1979–1984 Professor of School of Medicine, Osaka University
1984–2005 Professor of Faculty of Medicine, Kyoto University
1996–2000 Director of Faculty of Medicine/Graduate School of Medicine, Kyoto University
2002–2004 Director of Faculty of Medicine/Graduate School of Medicine, Kyoto University
2005– Specially-Appointed Professor of Graduate School of Medicine, Kyoto University
2006–2017 Visiting Professor of Kyoto University
2006–2012 Executive Member of the Council for Science and Technology Policy, Cabinet Office
2012–2017 Chairman, Board of Directors, Shizuoka Prefectural University Corporation
2015– President of Foundation for Biomedical Research and Innovation
2017– Distinguished Professor of KUIAS

Selected Papers

  • T. Honjo, T. Kataoka, Organization of immunoglobulin heavy chain genes and allelic deletion model. Proc. Natl. Acad. Sci. USA 75, 2140–2144 (1978).
  • Y. Yaoita, T. Honjo, Deletion of immunoglobulin heavy chain genes from expressed allelic chromosome. Nature 286, 850–853 (1980).
  • Y. Ishida, Y. Agata, K. Shibahara, T. Honjo, Induced expression of PD-1, a novel member of the immunoglobulin gene superfamily, upon programmed cell death. EMBO J. 11, 3887–3895 (1992).
  • M. Muramatsu, K. Kinoshita, S. Fagarasan, S. Yamada, Y. Shinkai, T. Honjo, Class switch recombination and hypermutation require activation- induced cytidine deaminase (AID), a potential RNA editing enzyme. Cell 102, 553–563 (2000).
  • Y. Iwai, M. Ishida, Y. Tanaka, T. Okazaki, T. Honjo, N. Minato, Involvement of PD-L1 on tumor cells in the escape from host immune system and tumor immunotherapy by PD-L1 blockade. Proc. Natl. Acad. Sci. USA 99, 12293–12297 (2002).


Noguchi Hideyo-Memorial Award for Medicine (1981), Asahi Prize (1982), The Imperial Prize and the Japan Academy Prize (1996), Person of Cultural Merit (2000), Foreign Associate of U.S. National Academy of Sciences (2001), Thomson Leading Japanese Scientists in Emerging Research Fronts (2004), Robert Koch Prize (2012), Order of Culture, Japan (2013), Tang Prize, Biopharmaceutical Science Award (2014), William B. Coley Award (2014), JCA-CHAAO Award (2014), Richard V. Smalley, MD Memorial Award (2015), Kyoto Prize (2016), The Keio Medical Science Prize (2016), Fudan-Zhongzhi Science Award in Biomedicine (2016)