Yoko Hamazaki

Professor, Center for iPS Cell Research and Application (CiRA) / Laboratory of Immunobiology, Graduate School of Medicine, Kyoto University
Immunology, Aging, Immunosenescence, T cells, Thymus, iPS cells

Title of Presentation

“Exploring Immunosenescence: Paving the Way for Heathy Aging”

The immune system normally eliminates pathogens and cancer cells. With age, its function gradually declines, which raises the risk that an infection could become serious or a cancer could develop. At the same time, the risk of some other immune responses, such as inflammation and autoimmunity, increases, potentially resulting in the development of a range of age-related diseases. This phenomenon of immunosenescence, with its two sides that appear to conflict with one another, can be a common underlying factor behind different diseases that increase with age. What it really is, or what causes it to happen, remains largely unknown, however.

T cells are immune cells that play a central role in the adaptive immune response. They regulate the functions of antibody-producing B cells as well as phagocytes, while directly killing cancerous or virus-infected cells. In spite of such critical roles they play, the thymus, the organ that produces and matures T cells, reaches its peak in early childhood and gradually decreases in size as the fat that surrounds it increases (i.e., thymus involution). By the time one is in their 20s, the number of T cells newly produced declines to below one-tenth of that in neonatal life. This means that T cells need to be maintained in the body for a long period of time, which makes them the immune cells that are most susceptible to the effect of aging.

In our research, my colleagues and I aim to gain better understanding of how thymus development and involution occurs, and how the fact that the T cell production declines at a relatively early age in life could be related to a range of diseases that increase with age, as well as to develop technologies to prevent or intervene against such diseases. It is also important to identify what causes substantial differences observed among individuals in the course and degree of the aging, even though its development takes a largely similar time course in a majority of people. In this presentation, I will discuss these points with reference to a study we recently conducted, which compared SARS-CoV-2 reactive T cells in young people in their 20s to those in elderly people in their 70s.

Human life expectancy is expected to increase further. Some estimate that young people who are in their 20s today may on average live to the age of 100 years or older. This means that we will need to maintain our T cells in good condition for an even longer period following thymus involution. Understanding immune characteristics of the elderly, whose population is set to continue expanding further, and providing healthcare that is appropriate for them, are urgent issues facing modern medicine in our effort to achieve a healthy aging society.



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A brief Biography(As of August 1, 2021)
Mar 1995 BS Faculty of Applied Biological Sciences, Hiroshima University
Mar 1997 MS Division of Hematology, Institute of Clinical Medicine, University of Tsukuba
Apr 1997 Pharmaceutical Division, Clinical Development Department, KIRIN Brewery Company, Limited.
Apr 1999 Graduate School of Medicine, Kyoto University
Apr 2002 Research Fellow, The Japan Society for the Promotion of Science (DC2)
Mar 2003 Ph.D. Department of Cell Biology, Graduate School of Medicine, Kyoto University (supervised by Dr. Shoichiro Tsukita)
Apr 2003 Assistant Professor, Department of Immunology and Cell Biology, Graduate School of Medicine, Kyoto University (supervised by Dr. Nagahiro Minato)
Dec 2010 Associate Professor, Department of Immunology and Cell Biology, Graduate School of Medicine, Kyoto University
May 2017-Present Professor, Department of Life Science Frontiers, Center for iPS Cell Research and Application (CiRA), Kyoto University
Jul 2017-Present Professor, Immunobiology, Graduate School of Medicine, Kyoto University
Details of selected Awards and Honors
A list of selected Publications