title: Free and complexed-secretory immunoglobulin A triggers distinct intestinal epithelial cell responses.
abstract: Secretory immunoglobulin A (SIgA) antibodies play an important role in protecting the mucosal surfaces against pathogens and maintaining homeostasis with the commensal microbiota. Because a substantial portion of the gut microbiota is coated with SIgA, we hypothesized that microbiota-SIgA complexes are important for the maintenance of gut homeostasis. Here we investigated the relationship between microbiota-SIgA complexes and inflammatory epithelial cell responses. We used a multi-cellular three-dimensional (3D) organotypical model of the human intestinal mucosa composed of an intestinal epithelial cell line and primary human lymphocytes/monocytes, endothelial cells and fibroblasts. We also used human SIgA from human colostrum, and a prominent bacterial member of the first colonizers, Escherichia coli, as a surrogate commensal. We found that free and microbiota-complexed SIgA triggered different epithelial responses. While free SIgA up-regulated mucus production, expression of polymeric immunoglobulin receptor (pIgR) and secretion of interleukin-8 and tumoir necrosis factor-α, microbiota-complexed SIgA mitigated these responses. These results suggest that free and complexed SIgA have different functions as immunoregulatory agents in the gut and that an imbalance between the two may affect gut homeostasis.
authors.affiliation: Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: R
authors.initials: R
authors.lastname: Salerno-Goncalves
authors.affiliation: Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: F
authors.initials: F
authors.lastname: Safavie
authors.affiliation: Mucosal Immunology and Biology Research Center, Massachusetts General Hospital for Children, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Fasano
authors.affiliation: Center for Vaccine Development, University of Maryland School of Medicine, Baltimore, MD, USA.
authors.forename: M B
authors.initials: MB
authors.lastname: Sztein
mesh_terms: D003126:Colostrum / Q000276:immunology; D004847:Epithelial Cells / Q000276:immunology*; D004926:Escherichia coli / Q000276:immunology / Q000502:physiology; D000069196:Gastrointestinal Microbiome / Q000276:immunology*; D006706:Homeostasis; D006801:Humans; D018928:Immunity, Mucosal / Q000276:immunology; D007071:Immunoglobulin A, Secretory / Q000737:chemistry* / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D007249:Inflammation; D016209:Interleukin-8 / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology; D007422:Intestines / Q000166:cytology / Q000276:immunology*; D009924:Organ Culture Techniques; D009940:Organoids / Q000166:cytology* / Q000187:drug effects / Q000276:immunology* / Q000382:microbiology; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism
chemical_list: D007071:Immunoglobulin A, Secretory; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha
keywords: SIgA; gut; human; mucosal immunity