한국에서 분리된 Vibrio harveyi 외막단백질의 유전적 차이와 넙치(Paralichthys olivaceus)에 대한 OmpW의 면역원성 분석

Abstract

Vibrio harveyi is a pathogenic marine bacterium causing systemic symptoms resulting in mass mortalities in fishes and shrimps in aquaculture. Outer membrane proteins(OMPs) are related to the pathogenicity and thus good targets for diagnosis and vaccination for Gram negative bacteria. Recently vaccination strategies using the OMPs have been suggested to control vibriosis in several fish species. In this study, we have isolated V. harveyi from diseased marine fishes from different regions of Korea and investigated genetic variations of four OMP genes including OmpK, OmpU, OmpV and OmpW. Consequently, OmpK and U genes could be divided into 3 subgroups of type I, II, III and type A, B, C, respectively, without any correlation with geographical regions and species while OmpV and W were highly homologous. OmpW gene of V. harveyi FP4138 was fully sequenced and predicted the deduced amino acid sequence to form <TEX>${\beta}-barrel$</TEX> with hydrophobic channel. Indeed, the immunogenicity of recombinant OmpW produced in Escherichia coli was assessed by vaccinating flounder. As a result, the high antibody response with antibody titer of <TEX>$4.2{\pm}0.7$</TEX> and protection with relative percent survival of 60% against artificial infection of V. harveyi were demonstrated. This result indicates that OmpW is a virulence related factor and it can be a vaccine candidate to prevent a high mortality caused by V. harveyi infection in olive flounder, Paralichthys olivaceus.