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Journal of Biomedicine and Biotechnology
Volume 2012, Article ID 760730, 8 pages
http://dx.doi.org/10.1155/2012/760730
Research Article

Generation of Biotechnology-Derived Flavobacterium columnare Ghosts by PhiX174 Gene E-Mediated Inactivation and the Potential as Vaccine Candidates against Infection in Grass Carp

1The Key Laboratory of Animal Resistance Biology of Shandong, College of Life Sciences, Shandong Normal University, Jinan 250014, China
2Shandong Key Laboratory of Animal Disease Control and Breeding, Shandong Academy of Agricultural Sciences, Jinan 250100, China

Received 6 February 2012; Accepted 5 April 2012

Academic Editor: Daniele Daffonchio

Copyright © 2012 Wenxing Zhu et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Flavobacterium columnare is a bacterial pathogen causing high mortality rates for many freshwater fish species. Fish vaccination with a safe and effective vaccine is a potential approach for prevention and control of fish disease. Here, in order to produce bacterial ghost vaccine, a specific Flavobacterium lysis plasmid pBV-E-cat was constructed by cloning PhiX174 lysis gene E and the cat gene with the promoter of F. columnare into the prokaryotic expression vector pBV220. The plasmid was successfully electroporated into the strain F. columnare G4cpN22 after curing of its endogenous plasmid. F. columnare G4cpN22 ghosts (FCGs) were generated for the first time by gene E-mediated lysis, and the vaccine potential of FCG was investigated in grass carp (Ctenopharyngodon idellus) by intraperitoneal route. Fish immunized with FCG showed significantly higher serum agglutination titers and bactericidal activity than fish immunized with FKC or PBS. Most importantly, after challenge with the parent strain G4, the relative percent survival (RPS) of fish in FCG group (70.9%) was significantly higher than FKC group (41.9%). These results showed that FCG could confer immune protection against F. columnare infection. As a nonliving whole cell envelope preparation, FCG may provide an ideal alternative to pathogen-based vaccines against columnaris in aquaculture.