| 研究実績の概要 |
We previously demonstrated that gut IgAs contribute to regulating the gut bacterial communities, but the mechanisms involved in such regulation remained unknown. We speculated that not only the repertoire but also the post-translational modifications might be different between IgAs elicited in different conditions (for example non-selected or “default” IgA versus adaptive, selected or “homeostatic” IgA). Thus we analyzed the properties of IgA from genetically modified mice lacking germinal centers, such as T cell deficient mice, or germ-free (GF) mice as well as gnotobiotic mice. We found that the “default” IgAs were heavily glycosylated and that the addition of bacteria drastically modified the sugar contents of IgAs. Sequencing analyses of bacteria coated with different IgA qualities will be analyzed in collaboration with the group of Professor Hattori. Furthermore, different bacterial species generated different glycosylation profiles, implicating that not only the immune system but also the microbiota contribute to biochemical characteristics of IgA in the gut. We began to dissect the importance of such post-translational modifications of IgA in the contexts of symbiotic interactions. The studies will be continued in the coming years. We believe that such fundamental research will contribute to deeper understanding of the basic principles governing the homeostasis at the mucosal surface. It will also allow envisioning strategies aiming to restore homeostasis in diseases accompanied by changes in microbiota composition and function.
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