Tasuku Honjo

Tasuku Honjo (本庶 佑, Honjo Tasuku, born January 27, 1942) is a distinguished Japanese physician-scientist and immunologist who revolutionized the field of cancer immunotherapy. He is most renowned for receiving the 2018 Nobel Prize in Physiology or Medicine, which he shared with James P. Allison, for their groundbreaking discoveries in cancer therapy through the inhibition of negative immune regulation.

Early Life and Education

Born in Kyoto, Japan, in 1942, Honjo pursued his medical education at Kyoto University's Faculty of Medicine, where he obtained his M.D. degree in 1966. He later earned his Ph.D. in Medical Chemistry in 1975 under the mentorship of Yasutomi Nishizuka and Osamu Hayaishi at the same institution.

Academic Career and Research Positions

Honjo's academic journey has been marked by several prestigious appointments across multiple institutions:

• 1971-1973: Visiting Fellow, Department of Embryology, Carnegie Institution of Washington
• 1973-1977: Fellow, National Institute of Child Health and Human Development, NIH
• 1974-1979: Assistant Professor, Faculty of Medicine, University of Tokyo
• 1979-1984: Professor, Department of Genetics, Osaka University School of Medicine
• 1984-2005: Professor, Department of Medical Chemistry, Kyoto University Faculty of Medicine
• 2005-present: Professor, Department of Immunology and Genomic Medicine, Kyoto University Faculty of Medicine
• 2012-2017: President, Shizuoka Prefecture Public University Corporation
• 2017-present: Deputy Director-General and Distinguished Professor, Kyoto University Institute for Advanced Study (KUIAS)

Major Scientific Contributions

Immunological Research

Honjo's research has made fundamental contributions to immunology, particularly in understanding the mechanisms of immune regulation and antibody diversity. His major scientific achievements include:

1. PD-1 Discovery: In 1992, Honjo identified Programmed Cell Death Protein 1 (PD-1), a breakthrough that laid the foundation for modern cancer immunotherapy. This discovery was instrumental in developing PD-1 blockade-based cancer treatments.
2. Cytokine Research: He successfully conducted molecular identification of several crucial cytokines:
   • Interleukin-4 (IL-4)
   • Interleukin-5 (IL-5)
   • Interleukin-2 receptor alpha chain
3. Antibody Diversification: Honjo established the basic conceptual framework of class switch recombination and discovered Activation-Induced Cytidine Deaminase (AID), which plays a vital role in:
   • Class switch recombination
   • Somatic hypermutation

Class Switch Recombination Model

Between 1980 and 1982, Honjo developed and verified a model explaining antibody gene rearrangement in class switch by elucidating its DNA structure. This work significantly advanced our understanding of immune system mechanisms.

COVID-19 Controversy

During the COVID-19 pandemic, Honjo became inadvertently involved in a controversy when false claims circulated on the internet suggesting he believed the novel coronavirus was manufactured in a laboratory in Wuhan, China. He publicly addressed these claims through Kyoto University's website, expressing his dismay at his name being used to spread misinformation.

Professional Affiliations

Honjo maintains several prestigious professional memberships:

• Member of the Japanese Society for Immunology (President, 1999-2000)
• Honorary member of the American Association of Immunologists
• Foreign Associate of the U.S. National Academy of Sciences (elected 2001)
• Member of the German Academy of Natural Scientists Leopoldina (elected 2003)
• Member of the Japan Academy (elected 2005)

Awards and Honors

Throughout his career, Honjo has received numerous prestigious awards and honors. Notable among these are:

Major Awards

• 2018: Nobel Prize in Physiology or Medicine
• 2016: Kyoto Prize in Basic Sciences
• 2014: Tang Prize in Biopharmaceutical Science
• 2013: Order of Culture (Japan)
• 2012: Robert Koch Prize
• 2000: Person of Cultural Merit (Japan)
• 1996: Imperial Prize of the Japan Academy

Honorary Doctorates

• 2024: National Taiwan University (First Japanese recipient)
• 2021: University of British Columbia
• 2020: Macau University of Science and Technology

Legacy

Tasuku Honjo's research has fundamentally transformed our understanding of the immune system and revolutionized cancer treatment approaches. His discovery of PD-1 and subsequent work in cancer immunotherapy has led to the development of new treatment options for various types of cancer, benefiting patients worldwide. His contributions continue to influence modern immunology and cancer research, cementing his position as one of the most significant figures in contemporary medical science.