Mechanism of intestinal midrobiota regulation by intestinal IgA

2017 Fiscal Year Final Research Report

• Project/Area Number: 15H04732
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: Bacteriology (including mycology)
• Research Institution: The University of Tokyo (2017); Nara Institute of Science and Technology (2016); Nagahama Institute of Bio-Science and Technology (2015)
• Principal Investigator: Shinkura Reiko 東京大学, 分子細胞生物学研究所, 教授 (50362471)
• Co-Investigator(Renkei-kenkyūsha): KUROKAWA Ken 国立遺伝学研究所, 生命情報研究センター, 教授 (20343246) ; MORI Hiroshi 国立遺伝学研究所, 生命情報研究センター, 助教 (40610837)
• Project Period (FY): 2015-04-01 – 2018-03-31
• Keywords: 粘膜免疫 / 抗体 / 腸内細菌

Outline of Final Research Achievements

Immunoglobulin A (IgA) is the main antibody isotype secreted into the intestinal lumen. IgA plays a critical role in the defense against pathogens and in the maintenance of intestinal homeostasis through gut microbial control. Our main question is what kind of bacterial molecule intestinal high-affinity IgA recognizes and targets. To address this question, we generated hybridomas from IgA producing cells in the small intestine of wild type mice. We selected W27 IgA that binds to multiple bacteria but not beneficial ones such as Lactobacillus casei. Via specific recognition of an epitope in serine hydroxymethyltransferase (SHMT), a bacterial metabolic enzyme, W27 IgA selectively inhibited the in vitro growth of Escherichia coli (E. coli), while having no effect on unbound beneficial bacteria such as L. casei. It indicates that W27 IgA has an ability to improve the intestinal environment.

Free Research Field

粘膜免疫学