Neonatal Fc receptor for IgG regulates mucosal immune responses to luminal bacteria
Masaru Yoshida, … , Wayne I. Lencer, Richard S. Blumberg
Masaru Yoshida, … , Wayne I. Lencer, Richard S. Blumberg
Published August 1, 2006
Citation Information: J Clin Invest. 2006;116(8):2142-2151. https://doi.org/10.1172/JCI27821.
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Research Article Gastroenterology

Neonatal Fc receptor for IgG regulates mucosal immune responses to luminal bacteria

Abstract

The neonatal Fc receptor for IgG (FcRn) plays a major role in regulating host IgG levels and transporting IgG and associated antigens across polarized epithelial barriers. Selective expression of FcRn in the epithelium is shown here to be associated with secretion of IgG into the lumen that allows for defense against an epithelium-associated pathogen (Citrobacter rodentium). This pathway of host resistance to a bacterial pathogen as mediated by FcRn involves retrieval of bacterial antigens from the lumen and initiation of adaptive immune responses in regional lymphoid structures. Epithelial-associated FcRn, through its ability to secrete and absorb IgG, may thus integrate luminal antigen encounters with systemic immune compartments and as such provide essential host defense and immunoregulatory functions at the mucosal surfaces.

Authors

Masaru Yoshida, Kanna Kobayashi, Timothy T. Kuo, Lynn Bry, Jonathan N. Glickman, Steven M. Claypool, Arthur Kaser, Takashi Nagaishi, Darren E. Higgins, Emiko Mizoguchi, Yoshio Wakatsuki, Derry C. Roopenian, Atsushi Mizoguchi, Wayne I. Lencer, Richard S. Blumberg

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Figure 5

Luminal bacterial antigens transported as an immune complex across intestinal epithelial cells via FcRn in vivo.

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Luminal bacterial antigens transported as an immune complex across intes...
(A and B) Flow cytometry of rabbit anti–E. coli IgG and control IgG followed by PE-conjugated goat anti-rabbit IgG (A) and FITC-conjugated E. coli (B). (C–F) Confocal microscopy analysis of transport of bacterial antigens across intestinal epithelial cells. Sections were stained for actin (phalloidin; red) and nuclei (blue). Magnification, ×400. Arrow in F illustrates transported FITC-conjugated E. coli in intestinal epithelial cells in the presence of rabbit anti–E. coli IgG. (G) Presence of FITC-conjugated E. coli in CD11c+ cells of the MLNs of IFABP-mFcRnTg/mβ2mTg/FcRn–/– mice 5 hours after FITC-conjugated E. coli administration in the presence of rabbit anti–E. coli IgG. Mean fluorescence intensity (MFI) on gated CD11c+ cells is shown. The mean ± SD was shown for each group (n = 4). *P < 0.05.