title: Outer membrane protein A (OmpA) binds to and activates human macrophages.
abstract: Outer membrane protein (Omp)A is highly represented and conserved in the Enterobacteriaceae family. Using a recombinant OmpA from Klebsiella pneumoniae (P40), we have analyzed the interaction between OmpA and macrophages. We report that Alexa488-labeled P40 binds (at 4 degrees C) to murine and human macrophages in a dose-dependent manner and is rapidly internalized (at 37 degrees C). No binding or internalization of the Alexa488-labeled glycophorin A control protein is observed under the same conditions. Furthermore, P40 up-regulates the production of IL-1beta, IL-8, IL-10, IL-12, and TNF-alpha by human macrophages and of NO by the RAW 264.7 murine macrophage cell line. P40 also synergizes with IFN-gamma and suboptimal concentrations of LPS to up-regulate the production of these mediators. In conclusion, P40 binds to and activates macrophages. These data suggest that recognition of OmpA by macrophages may be an initiating event in the antibacterial host response.
authors.affiliation: Centre d'Immunologie Pierre Fabre, Saint-Julien en Genevois, France.
authors.forename: C
authors.initials: C
authors.lastname: Soulas
authors.forename: T
authors.initials: T
authors.lastname: Baussant
authors.forename: J P
authors.initials: JP
authors.lastname: Aubry
authors.forename: Y
authors.initials: Y
authors.lastname: Delneste
authors.forename: N
authors.initials: N
authors.lastname: Barillat
authors.forename: G
authors.initials: G
authors.lastname: Caron
authors.forename: T
authors.initials: T
authors.lastname: Renno
authors.forename: J Y
authors.initials: JY
authors.lastname: Bonnefoy
authors.forename: P
authors.initials: P
authors.lastname: Jeannin
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology* / Q000378:metabolism* / Q000494:pharmacology; D002460:Cell Line; D002478:Cells, Cultured; D004357:Drug Synergism; D004705:Endocytosis / Q000276:immunology; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D008070:Lipopolysaccharides / Q000494:pharmacology; D008262:Macrophage Activation / Q000276:immunology*; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism*; D051379:Mice; D018613:Microscopy, Confocal; D008970:Molecular Weight; D011485:Protein Binding / Q000276:immunology
chemical_list: D001425:Bacterial Outer Membrane Proteins; D008070:Lipopolysaccharides; C078167:OMPA outer membrane proteins; D007371:Interferon-gamma