title: Search for live attenuated vaccine candidate against edwardsiellosis by mutating virulence-related genes of fish pathogen Edwardsiella tarda.
abstract: OBJECTIVE
  The aims of this study were to construct and evaluate the live attenuated vaccine against edwardsiellosis on zebra fish model.
  
  
  RESULTS
  In this study, the deletion mutant of aroC gene for the biosynthesis of chorismic acid in Edwardsiella tarda EIB202 was firstly constructed by allelic exchange strategy. According to the genome information, 19 double mutants and one multiple mutant were successively constructed by deleting virulence-associated genes based on the ΔaroC mutant. Zebra fish model was used to assay the virulence of the mutants by intramuscular (i.m.) injection. Fourteen mutants were significantly attenuated with accumulated mortality ranged from 0 to 63% (P<0.05). The zebra fish vaccinated with ΔaroC, ΔaroCΔesrC, ΔaroCΔslyA and ΔaroCΔeseBCDΔesaC via i.m. injection showed ideal protection, resulting in relative per cent survival (RPS) of 68.3, 71.3, 80.1 and 81% against subsequent challenge with the wild-type Edw. tarda EIB202.
  
  
  CONCLUSIONS
  ΔaroCΔeseBCDΔesaC behaved a low virulence and the highest RPS on zebra fish model. When the zebra fish were vaccinated with ΔaroCΔeseBCDΔesaC via injection, the expression of immune-related factors including IgM and MHC II was up-regulated.
  
  
  CONCLUSIONS
  The mutant ΔaroCΔeseBCDΔesaC might serve as an effective live attenuated vaccine against edwardsiellosis.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, China.
authors.forename: J
authors.initials: J
authors.lastname: Xiao
authors.forename: T
authors.initials: T
authors.lastname: Chen
authors.forename: Q
authors.initials: Q
authors.lastname: Wang
authors.forename: Q
authors.initials: Q
authors.lastname: Liu
authors.forename: X
authors.initials: X
authors.lastname: Wang
authors.forename: Y
authors.initials: Y
authors.lastname: Lv
authors.forename: H
authors.initials: H
authors.lastname: Wu
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
mesh_terms: D000818:Animals; D001428:Bacterial Vaccines / Q000235:genetics / Q000276:immunology; D020609:Edwardsiella tarda / Q000235:genetics / Q000276:immunology* / Q000472:pathogenicity; D004756:Enterobacteriaceae Infections / Q000276:immunology / Q000517:prevention & control / Q000662:veterinary*; D005393:Fish Diseases / Q000276:immunology / Q000382:microbiology / Q000517:prevention & control*; D009154:Mutation; D014613:Vaccines, Attenuated / Q000235:genetics / Q000276:immunology; D014774:Virulence / Q000235:genetics; D015027:Zebrafish / Q000235:genetics / Q000276:immunology / Q000382:microbiology
chemical_list: D001428:Bacterial Vaccines; D014613:Vaccines, Attenuated