title: Growth and host interaction of mouse segmented filamentous bacteria in vitro.
abstract: The gut microbiota plays a crucial role in the maturation of the intestinal mucosal immune system of its host. Within the thousand bacterial species present in the intestine, the symbiont segmented filamentous bacterium (SFB) is unique in its ability to potently stimulate the post-natal maturation of the B- and T-cell compartments and induce a striking increase in the small-intestinal Th17 responses. Unlike other commensals, SFB intimately attaches to absorptive epithelial cells in the ileum and cells overlying Peyer's patches. This colonization does not result in pathology; rather, it protects the host from pathogens. Yet, little is known about the SFB-host interaction that underlies the important immunostimulatory properties of SFB, because SFB have resisted in vitro culturing for more than 50 years. Here we grow mouse SFB outside their host in an SFB-host cell co-culturing system. Single-celled SFB isolated from monocolonized mice undergo filamentation, segmentation, and differentiation to release viable infectious particles, the intracellular offspring, which can colonize mice to induce signature immune responses. In vitro, intracellular offspring can attach to mouse and human host cells and recruit actin. In addition, SFB can potently stimulate the upregulation of host innate defence genes, inflammatory cytokines, and chemokines. In vitro culturing thereby mimics the in vivo niche, provides new insights into SFB growth requirements and their immunostimulatory potential, and makes possible the investigation of the complex developmental stages of SFB and the detailed dissection of the unique SFB-host interaction at the cellular and molecular levels.
authors.affiliation: 1] Unité de Pathogénie Microbienne Moleculaire and Institut national de la santé et de la recherche médicale (INSERM) unit U786, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris Cedex 15, France [2] INSERM, UMR1163, Laboratory of Intestinal Immunity, Institut Imagine, 24, Boulevard du Montparnasse, 75015 Paris, France.
authors.forename: Pamela
authors.initials: P
authors.lastname: Schnupf
authors.affiliation: 1] INSERM, UMR1163, Laboratory of Intestinal Immunity, Institut Imagine, 24, Boulevard du Montparnasse, 75015 Paris, France [2] Institut national de la recherche agronomique (INRA) Micalis UMR1319, 78350 Jouy-en-Josas, France [3] Université Paris Descartes-Sorbonne Paris Cité and Institut Imagine, 75015 Paris, France.
authors.forename: Valérie
authors.initials: V
authors.lastname: Gaboriau-Routhiau
authors.affiliation: 1] Université Paris Descartes-Sorbonne Paris Cité and Institut Imagine, 75015 Paris, France [2] Ecole Normale Superieure de Lyon, Department of Biology, 69007 Lyon, France.
authors.forename: Marine
authors.initials: M
authors.lastname: Gros
authors.affiliation: Unité de Pathogénie Microbienne Moleculaire and Institut national de la santé et de la recherche médicale (INSERM) unit U786, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris Cedex 15, France.
authors.forename: Robin
authors.initials: R
authors.lastname: Friedman
authors.affiliation: Imagopole, Ultrastructural Microscopy Platform, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris Cedex 15, France.
authors.forename: Maryse
authors.initials: M
authors.lastname: Moya-Nilges
authors.affiliation: Unité de Pathogénie Microbienne Moleculaire and Institut national de la santé et de la recherche médicale (INSERM) unit U786, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris Cedex 15, France.
authors.forename: Giulia
authors.initials: G
authors.lastname: Nigro
authors.affiliation: 1] INSERM, UMR1163, Laboratory of Intestinal Immunity, Institut Imagine, 24, Boulevard du Montparnasse, 75015 Paris, France [2] Université Paris Descartes-Sorbonne Paris Cité and Institut Imagine, 75015 Paris, France.
authors.forename: Nadine
authors.initials: N
authors.lastname: Cerf-Bensussan
authors.affiliation: 1] Unité de Pathogénie Microbienne Moleculaire and Institut national de la santé et de la recherche médicale (INSERM) unit U786, Institut Pasteur, 25-28 Rue du Dr Roux, 75724 Paris Cedex 15, France [2] Microbiologie et Maladies Infectieuses, Collège de France, 11 Marcelin Berthelot Square, 75005 Paris, France.
authors.forename: Philippe J
authors.initials: PJ
authors.lastname: Sansonetti
mesh_terms: D000199:Actins / Q000378:metabolism; D000818:Animals; D001419:Bacteria / Q000166:cytology / Q000254:growth & development* / Q000276:immunology*; D002460:Cell Line; D018920:Coculture Techniques / Q000379:methods*; D004926:Escherichia coli / Q000166:cytology / Q000254:growth & development / Q000276:immunology; D005243:Feces / Q000382:microbiology; D005260:Female; D005856:Germ-Free Life; D006801:Humans; D018928:Immunity, Mucosal / Q000276:immunology; D007413:Intestinal Mucosa / Q000166:cytology / Q000276:immunology / Q000382:microbiology; D007422:Intestines / Q000166:cytology / Q000276:immunology* / Q000382:microbiology*; D008214:Lymphocytes / Q000166:cytology / Q000276:immunology*; D008297:Male; D051379:Mice; D050296:Microbial Viability; D010581:Peyer's Patches / Q000276:immunology; D013559:Symbiosis / Q000276:immunology*; D058504:Th17 Cells / Q000276:immunology
chemical_list: D000199:Actins