title: Isolation of a novel gene from Photobacterium damselae subsp. piscicida and analysis of the recombinant antigen as promising vaccine candidate.
abstract: Photobacterium damselae subsp. piscicida (PDP) is the causative agent of fish pasteurellosis, a bacterial disease causing important losses in marine aquaculture. Vaccines against the pathogen can be a way to control the infection and avoid antibiotic treatments. However, a satisfactory protective vaccine against fish pasteurellosis is not commercially available. In this study, a biotechnogical approach based on reverse vaccinology has been used to identify potential vaccine candidates for the development of a recombinant subunit vaccine. Genome sequencing of clones from a genomic cosmid library of PDP and in silico selection of the surface exposed proteins were the initial steps in vaccine candidate identification. From 370 open reading frames (ORF) eight potential antigens were selected, expressed as recombinant proteins and purified. These vaccine candidates were used to generate specific polyclonal antibodies in mice. Each antibody was then screened in vitro by inhibition adherence assay of live PDP on chinook salmon embryo cells (CHSE-214). A lipoprotein, found to be involved in the adherence of the bacterium to epithelial cells and annotated as PDP_0080, was then selected. The recombinant protein was further investigated in fish vaccination and challenge experiments to assess its ability to protect sea bass, Dicentrarchus labrax, against PDP infection. Immunisation with PDP_0080 recombinant protein elicited high specific antibody titres. Furthermore, the survival rate of fish immunized with the 25 μg dose of protein was significantly higher compared to the control group. The results of the study suggest that the PDP_0080 protein could be a promising candidate for the design of a recombinant vaccine against pasteurellosis.
authors.affiliation: Department of Biomolecular Science, Section of Biotechnology, University of Urbino, via Campanella 1, 61032 Fano, Italy. francesca.andreoni@uniurb.it
authors.forename: Francesca
authors.initials: F
authors.lastname: Andreoni
authors.forename: Romina
authors.initials: R
authors.lastname: Boiani
authors.forename: Giordano
authors.initials: G
authors.lastname: Serafini
authors.forename: Giulia
authors.initials: G
authors.lastname: Amagliani
authors.forename: Sabrina
authors.initials: S
authors.lastname: Dominici
authors.forename: Giulia
authors.initials: G
authors.lastname: Riccioni
authors.forename: Renata
authors.initials: R
authors.lastname: Zaccone
authors.forename: Monique
authors.initials: M
authors.lastname: Mancuso
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Scapigliati
authors.forename: Mauro
authors.initials: M
authors.lastname: Magnani
mesh_terms: D000818:Animals; D000942:Antigens, Bacterial / Q000235:genetics / Q000276:immunology*; D001428:Bacterial Vaccines / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology*; D001492:Bass; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D005393:Fish Diseases / Q000276:immunology / Q000517:prevention & control*; D008969:Molecular Sequence Data; D010326:Pasteurella Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D010776:Photobacterium / Q000235:genetics / Q000276:immunology*; D017422:Sequence Analysis, DNA; D014614:Vaccines, Synthetic / Q000008:administration & dosage / Q000235:genetics / Q000276:immunology
chemical_list: D000942:Antigens, Bacterial; D001428:Bacterial Vaccines; D004269:DNA, Bacterial; D014614:Vaccines, Synthetic