title: Antigen Uptake during Different Life Stages of Zebrafish (Danio rerio) Using a GFP-Tagged Yersinia ruckeri.
abstract: Immersion-vaccines (bacterins) are routinely used for aquacultured rainbow trout to protect against Yersinia ruckeri (Yr). During immersion vaccination, rainbow trout take up and process the antigens, which induce protection. The zebrafish was used as a model organism to study uptake mechanisms and subsequent antigen transport in fish. A genetically modified Yr was developed to constitutively express green fluorescent protein (GFP) and was used for bacterin production. Larval, juvenile and adult transparent zebrafish (tra:nac mutant) received a bath in the bacterin for up to 30 minutes. Samples were taken after 1 min, 15 min, 30 min, 2 h, 12 h and 24 h. At each sampling point fish were used for live imaging of the uptake using a fluorescence stereomicroscope and for immunohistochemistry (IHC). In adult fish, the bacterin could be traced within 30 min in scale pockets, skin, oesophagus, intestine and fins. Within two hours post bath (pb) Yr-antigens were visible in the spleen and at 24 h in liver and kidney. Bacteria were associated with the gills, but uptake at this location was limited. Antigens were rarely detected in the blood and never in the nares. In juvenile fish uptake of the bacterin was seen in the intestine 30 min pb and in the nares 2 hpb but never in scale pockets. Antigens were detected in the spleen 12 hpb. Zebrafish larvae exhibited major Yr uptake only in the mid-intestine enterocytes 24 hpb. The different life stages of zebrafish varied with regard to uptake locations, however the gut was consistently a major uptake site. Zebrafish and rainbow trout tend to have similar uptake mechanisms following immersion or bath vaccination, which points towards zebrafish as a suitable model organism for this aquacultured species.
authors.affiliation: Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Rozalia
authors.initials: R
authors.lastname: Korbut
authors.affiliation: Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Foojan
authors.initials: F
authors.lastname: Mehrdana
authors.affiliation: Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Per Walter
authors.initials: PW
authors.lastname: Kania
authors.affiliation: Food Safety and Zoonoses, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Marianne Halberg
authors.initials: MH
authors.lastname: Larsen
authors.affiliation: Food Safety and Zoonoses, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Dorte
authors.initials: D
authors.lastname: Frees
authors.affiliation: Section for Bacteriology and Pathology, National Veterinary Institute, Technical University of Denmark, Frederiksberg, Denmark.
authors.forename: Inger
authors.initials: I
authors.lastname: Dalsgaard
authors.affiliation: Laboratory of Aquatic Pathobiology, Department of Veterinary Disease Biology, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Louise von Gersdorff
authors.initials: Lv
authors.lastname: Jørgensen
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000276:immunology / Q000378:metabolism*; D001428:Bacterial Vaccines / Q000276:immunology / Q000378:metabolism; D049452:Green Fluorescent Proteins / Q000235:genetics*; D008018:Life Cycle Stages; D009154:Mutation; D014611:Vaccination; D044124:Yersinia ruckeri / Q000235:genetics* / Q000276:immunology*; D015027:Zebrafish / Q000235:genetics / Q000254:growth & development* / Q000276:immunology / Q000378:metabolism*
chemical_list: D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D049452:Green Fluorescent Proteins