Selective adherence of IgA to murine Peyer's patch M cells: evidence for a novel IgA receptor

NJ Mantis, MC Cheung… - The Journal of …, 2002 - journals.aai.org
NJ Mantis, MC Cheung, KR Chintalacharuvu, J Rey, B Corthésy, MR Neutra
The Journal of Immunology, 2002journals.aai.org
M cells represent the primary route by which mucosal Ags are transported across the
intestinal epithelium and delivered to underlying gut-associated lymphoid tissues. In rodents
and rabbits, Peyer's patch M cells selectively bind and endocytose secretory IgA (SIgA) Abs.
Neither the nature of the M cell IgR nor the domains of SIgA involved in this interaction are
known. Using a mouse ligated ileal loop assay, we found that monoclonal IgA Abs with or
without secretory component, but not IgG or IgM Abs, bound to the apical surfaces of Peyer's …
Abstract
M cells represent the primary route by which mucosal Ags are transported across the intestinal epithelium and delivered to underlying gut-associated lymphoid tissues. In rodents and rabbits, Peyer’s patch M cells selectively bind and endocytose secretory IgA (SIgA) Abs. Neither the nature of the M cell IgR nor the domains of SIgA involved in this interaction are known. Using a mouse ligated ileal loop assay, we found that monoclonal IgA Abs with or without secretory component, but not IgG or IgM Abs, bound to the apical surfaces of Peyer’s patch M cells, indicating that the receptor is specific for the IgA isotype. Human serum IgA and colostral SIgA also bound to mouse M cells. The asialoglycoprotein receptor or other lectin-like receptors were not detected on the apical surfaces of M cells. We used recombinant human IgA1 and human IgA2 Abs and domain swapped IgA/IgG chimeras to determine that both domains Cα1 and Cα2 are required for IgA adherence to mouse Peyer’s patch M cells. This distinguishes the M cell IgA receptor from CD89 (FcαI), which binds domains Cα2-Cα3. Finally, we observed by immunofluorescence microscopy that some M cells in the human ileum are coated with IgA. Together these data suggest that mouse, and possibly human, M cells express an IgA-specific receptor on their apical surfaces that mediates the transepithelial transport of SIgA from the intestinal lumen to underlying gut-associated organized lymphoid tissues.
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