Prof. Takehiko Sasazuki
*1940 † 2023
On February 1st of this year the immunological community lost one of their prominent members, Takehiko Sasazuki, Professor Emeritus of the Institute for Advanced Study Kyushu University, who was an honorary member of the German Society for Immunology.
Takehiko Sasazuki was born in 1940. His father was a professor for Japanese literature and his grandfather from his mother’s side a professor for engineering. His home was often visited by his father’s colleagues and pupils of his grandfather which fostered his desire to also become a scholar. But as his interest lay more in the medical field, he studied medicine at the Kyushu University School of Medicine. After moving to the prestigious Tokyo Medical and Dental University he worked on the polymorphism of human haptoglobins Hp which had been indicated to influence antibody production against various strains of bacteria. Stimulated by this topic he joined the laboratory of the immunology star Hugh McDevitt at Stanford University Medical School as a postdoc in 1973. This is where we met and developed a lifelong and close friendship.
Using a set of well-defined synthetic polypeptide antigens generated by Michael Sela, the later director of the Weizmann Institute in Rehovot, Israel, McDevitt had just made the surprising discovery that in inbred strains of mice the ability to generate strong antibody responses against the polypeptide antigens was controlled by a novel set of genes, then named immune response (Ir) genes. The Ir genes could be mapped to the major histocompatibility locus (MHC). Initially they were assumed to encode the elusive T cell receptor, not an unreasonable hypothesis, but soon the Ir gene products were found to be expressed on B cells and macrophages, and later identified as a new class of MHC antigens, the now well-known MHC class II antigens. Takehiko set out to study whether or not in humans antibody production against vaccines such as tetanus or diphtheria was also controlled by the polymorphism of the human major histocompatiblity antigens HLA. These studies were extended to human autoimmune diseases, which were also found to depend on particular HLA alleles. Together with the work of Rolf Zinkernagel and Peter Doherty these discoveries established the importance of the hitherto unknown biological function of MHC molecules as structures that are crucial for directing the immune defense against the world of environmental pathogens. Thus, these studies initiated the later demonstration of peptide binding by MHC molecules and antigen presentation pathways, and its clinical application of well-designed vaccines in the fields of infectious diseases, allergy and cancer.
After returning to Japan Takehiko continued to elucidate the role of HLA alleles in controlling immune related diseases including allergies, autoimmune diseases and graft versus host disease. Through this work he won world-wide recognition and was appointed to high-ranking positions including President of the International Medical Center of Japan. Stimulated by his ample personal international interactions he also wanted to make Japanese immunology internationally more visible. Thus, when he was president of the Japanese Society of Immunology, he invited leading immunologists from Europe, USA and Canada for the 1995 annual meeting and urged his Japanese colleagues to present their lectures and posters in English. In order to strengthen the interaction with Germany he suggested to Fritz Melchers and myself the establishment of a series of bi-national meetings alternating in Germany and Japan in which about 12-14 scientists from each country would stay at the same hotel for a couple of days and get to know each other and discuss science, develop collaborative projects and potentially exchange scientists. The German Research Council (DFG) approved of this idea and supported it with funds. The first meeting took place in Bamberg in 1996. So far, a total of 11 meetings were held in either Japan or in Germany, with German organizers including Jochen Kalden, Klaus Eichmann, Andreas Radbruch and Jochen Hühn. When the meetings took place in Japan, often at traditional hot spring spas, Takehiko`s hospitality was legendary.
Takehiko was a very cheerful and social person who easily made friends. He was always ready to tell an anecdote or a joke but also to discuss science. Like many Japanese of his generation, he knew some German, probably due to the fact that during the Meiji era at the end of the 19th century the Japanese medical system was modeled on the German system, with German instructors visiting Japan and texts based on German textbooks. Takehiko liked to recite poems by Goethe and smiled politely (and pleased) when he knew them better than his German colleagues.
He leaves behind his wife, an accomplished pianist, two daughters who are clinicians in Japan, and five grandchildren. We mourn for this great scientist, friend and colleague.
by Günter J. Hämmerling (DGfI president 1997-1998), Heidelberg February 2023