August 23, 2019
Keio University Faculty of Pharmacy
National Center for Global Health and Medicine
In a joint study with the National Center for Global Health and Medicine (NCGM), the Keio University Faculty of Pharmacy has discovered the mechanism by which the antigen-specific immune response, crucial for maintaining gut health, is lost due to fasting. This achievement is the result of a research group led by Mototsugu Nagai (a student in the Doctoral Programs), Professor Koji Hase, and Guest Professor Taeko Dohi from the Keio University Faculty of Pharmacy, and Yuki Kawamura, Head of the Laboratory of Gastrointestinal Pathophysiology, Center for Hepatitis and Immunology Research at NCGM.
Globally, approximately 700 million people live in absolute poverty, unable to secure even the minimum necessary nutrition, which is an international issue. Furthermore, it has been reported that children suffering from malnutrition due to conflict or famine are more susceptible to infectious diseases and that the efficacy of vaccines is lower in these children. The key to vaccine efficacy lies in the establishment of memory (immunological memory) in the immune system. While it was previously known that nutrition affects the function of the immune system, the changes in the immune system during a state of fasting, where nutrition is cut off, had been largely unelucidated. The research group has now discovered that during temporary fasting, germinal center B cells, which are crucial for the formation of immunological memory in the Peyer's patches of the gut, undergo cell death. On the other hand, they revealed that naive B cells, before activation, temporarily retreat to the bone marrow during fasting and promptly return to the Peyer's patches after refeeding. Therefore, it was found that when fasting and refeeding are performed after the administration of an oral vaccine, only the activated germinal center B cells are eliminated, significantly reducing the efficacy of the oral vaccine.
This study not only reveals part of the mechanism by which the immune system adapts to starvation but also suggests that the immune response can be controlled by nutritional signals. It is hoped that further research will lead to the development of effective vaccination methods through dietary intervention. The results of this research were published in the international academic journal "Cell" on August 22, 2019 (U.S. Eastern Time).
For the full press release, please see below.