Expression,Characterization and Immunogenicity of a Major Outer Membrane Protein from Vibrio alginolyticus

Vibrio alginolyticus is one of the Vibrio pathogens common to humans and marine animals.During infection and induction of the host immune response,outer membrane proteins of bacteria play animportant role.In this study,an outer membrane protein gene(ompW)was cloned from V.alginolyticus andexpressed in Escherichia coli.The 645 bp open reading frame(ORF)encodes a protein of 214 amino acidresidues with a predicted molecular weight of 23.3 kDa.The amino acid sequence showed a high identitywith that of Photobacterium damselae(96.2%)and Vibrio parahaemolyticus(94.4%).The alignment analy-sis indicated that OmpW was highly conserved.Sodium dodecyl sulfate-polyacrylamide gel electrophoresisshowed that the gene was over-expressed in E.coli BL21(DE3).Western blot analysis revealed that theexpressed protein had immunoreactivity.The recombinant protein was purified by affinity chromatographyon Ni-NTA Superflow resin.Large yellow croaker vaccinated with the purified OmpW showed significantlyincreased antibody to OmpW,which could resist the infection by V.alginolyticus.A specific antibody wasdetected by enzyme-linked immunosorbent assay.This study suggested that the conserved OmpW could bean effective vaccine candidate against infection by V.alginolyticus.