Peyer’s patches (PPs) are the major mucosal immune-inductive site, and germinal centers (GCs) in PPs determine the quality of the Abs produced. PP GCs are continuously induced by the gut microbiota, and their maintenance contributes to the induction of strong IgA responses to Ags. In this study, we investigated the role of formyl peptide receptor (FPR)-mediated signaling in the maintenance of PP GCs, because FPRs recognize the microbiota and initiate an innate immune response by chemotaxis. We found that follicular dendritic cells (FDCs), a key organizer of B cell follicles and GCs in mucosal immunity, express Fpr2. Additionally, Fpr2-mediated signaling in PP FDCs promoted Cxcl13 and B cell activating factor expression, as well as B cell proliferation and activation. Therefore, we suggest that Fpr2-mediated signaling in FDCs plays a key role in GC maintenance in PPs and results in an Ag-specific IgA response in the gut mucosal immune compartment.
This work was supported by Grants 2014K1B1A1073861 (to Y.-S.J.) and 2014R1A1A3051207 (to S.-H.K.) through the National Research Foundation, which is funded by the Korean Ministry of Science, ICT, and Future Planning, as well as by Grant HI15C3039 (to Y.-S.J.) through the Korea Health Industry Development Institute, which is funded by the Korean Ministry of Health and Welfare. Y.-S.J. was supported by the Research Base Construction Fund Support Program funded by Chonbuk National University in 2016, S.-H.K. was supported by the Program of National University for Innovation and Transformation, and Y.N.K. was supported by the BK21 PLUS program in the Department of Bioactive Material Sciences.
The online version of this article contains supplemental material.
Abbreviations used in this article:
- 7-aminoactinomycin D
- B cell activating factor
- confocal laser scanning microscopy
- cathelin-related antimicrobial peptide
- follicular dendritic cell
- formyl peptide receptor
- mouse FPR
- germinal center
- lamina propria
- peripheral lymph node
- Peyer’s patch
- PP lymphocyte
- quantitative real-time PCR
- specific pathogen-free
- Received May 26, 2016.
- Accepted November 14, 2016.
- Copyright © 2017 by The American Association of Immunologists, Inc.