Elucidating the role of IgA in host-bacterial symbiosis in the gut

2015 Fiscal Year Final Research Report

• Project/Area Number: 25293118
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Immunology
• Research Institution: Institute of Physical and Chemical Research
• Principal Investigator: Fagarasan Sidonia 国立研究開発法人理化学研究所, 統合生命医科学研究センター, チームリーダー (00391970)
• Project Period (FY): 2013-04-01 – 2016-03-31
• Keywords: IgA / 腸内細菌叢

Outline of Final Research Achievements

During our studies we obtained solid evidence that specific arms of the adaptive immune system play critical roles in controlling the structures of commensal bacteria in the gut. We found that Foxp3+T cells facilitate the diversification of bacteria responsible for immune homeostasis particularly species belonging to Firmicutes. We revealed that such control of indigenous bacteria by Foxp3+ T cells involved regulatory functions consisting of suppression of inflammation and regulation of IgA selection in Peyer's patches. We found that diversified and selected IgAs repertoires regulated by Foxp3+ T cells are moderately coating a large diversity of bacteria species thus contributing to their maintenance in the gut. In contrast, IgAs elicited in the absence of T cells abundantly coat bacterial species leading to their elimination rather than retention. Our results mark a paradigm shift in our understanding of immune-bacteria symbiosis in the gut (Kawamoto et al, Immunity 2014).

Free Research Field

Immunology