title: Vaccination with outer membrane vesicles from Francisella noatunensis reduces development of francisellosis in a zebrafish model.
abstract: Infection of fish with the facultative intracellular bacterium Francisella noatunensis remains an unresolved problem for aquaculture industry worldwide as it is difficult to vaccinate against without using live attenuated vaccines. Outer membrane vesicles (OMVs) are biological structures shed by Gram-negative bacteria in response to various environmental stimuli. OMVs have successfully been used to vaccinate against both intracellular and extracellular pathogens, due to an ability to stimulate innate, cell-mediated and humoral immune responses. We show by using atomic force and electron microscopy that the fish pathogenic bacterium F. noatunensis subspecies noatunensis (F.n.n.) shed OMVs both in vitro into culture medium and in vivo in a zebrafish infection model. The main protein constituents of the OMV are IglC, PdpD and PdpA, all known Francisella virulence factors, in addition to the outer membrane protein FopA and the chaperonin GroEL, as analyzed by mass spectrometry. The vesicles, when used as a vaccine, reduced proliferation of the bacterium and protected zebrafish when subsequently challenged with a high dose of F.n.n. without causing adverse effects for the host. Also granulomatous responses were reduced in F.n.n.-challenged zebrafish after OMV vaccination. Taken together, the data support the possible use of OMVs as vaccines against francisellosis in fish.
authors.affiliation: Section for Microbiology, Immunology and Parasitology, Department of Food Safety and Infection Biology, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033 Oslo, Norway; Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Espen
authors.initials: E
authors.lastname: Brudal
authors.affiliation: Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Elisabeth O
authors.initials: EO
authors.lastname: Lampe
authors.affiliation: Department of Pharmaceutical Chemistry, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Léon
authors.initials: L
authors.lastname: Reubsaet
authors.affiliation: Department of Biosciences, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Norbert
authors.initials: N
authors.lastname: Roos
authors.affiliation: Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Ida K
authors.initials: IK
authors.lastname: Hegna
authors.affiliation: Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway.
authors.forename: Ida Marie
authors.initials: IM
authors.lastname: Thrane
authors.affiliation: Section for Anatomy and Pathology, Department of Basic Sciences and Aquatic Medicine, Norwegian University of Life Sciences, PO Box 8146 Dep, 0033 Oslo, Norway.
authors.forename: Erling O
authors.initials: EO
authors.lastname: Koppang
authors.affiliation: Laboratory for Microbial Dynamics (LaMDa), School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway; Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, PO Box 1068 Blindern, 0316 Oslo, Norway. Electronic address: hannewi@farmasi.uio.no.
authors.forename: Hanne C
authors.initials: HC
authors.lastname: Winther-Larsen
mesh_terms: D000818:Animals; D001425:Bacterial Outer Membrane Proteins / Q000276:immunology*; D001428:Bacterial Vaccines / Q000494:pharmacology*; D002853:Chromatography, Liquid; D004591:Electrophoresis, Polyacrylamide Gel; D005603:Francisella / Q000276:immunology* / Q000648:ultrastructure; D016905:Gram-Negative Bacterial Infections / Q000517:prevention & control*; D056724:Immunity, Humoral / Q000187:drug effects / Q000276:immunology*; D053208:Kaplan-Meier Estimate; D018625:Microscopy, Atomic Force; D046529:Microscopy, Electron, Transmission; D053719:Tandem Mass Spectrometry; D022161:Transport Vesicles / Q000276:immunology* / Q000648:ultrastructure; D014611:Vaccination / Q000379:methods*; D015027:Zebrafish
chemical_list: D001425:Bacterial Outer Membrane Proteins; D001428:Bacterial Vaccines
keywords: Francisella; Outer membrane vesicles; Vaccine; Zebrafish