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ARS Home » Southeast Area » Auburn, Alabama » Aquatic Animal Health Research » Research » Publications at this Location » Publication #267817
Title: Identification of immunogenic proteins within distinct molecular mass fractions of Flavobacterium psychrophilum

Author
item Lafrentz, Benjamin
item LAPATRA, SCOTT - Clear Springs Foods, Inc
item CALL, DOUGLAS - Washington State University
item Wiens, Gregory - Greg
item CAIN, KENNETH - University Of Idaho

Submitted to: Journal of Fish Diseases
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/27/2011
Publication Date: 10/12/2011
Citation: Lafrentz, B.R., Lapatra, S.E., Call, D.R., Wiens, G.D., Cain, K.D. 2011. Identification of immunogenic proteins within distinct molecular mass fractions of Flavobacterium psychrophilum. Journal of Fish Diseases. 34:823-830.

Interpretive Summary: Flavobacterium psychrophilum is an economically important bacterial pathogen of salmonid aquaculture and accounts for millions of dollars of losses annually worldwide. Previous research demonstrated that immunization of rainbow trout with distinct size fractions of proteins from F. psychrophilum resulted in solid protection following inoculation of fish with the bacterium. Specific antibodies against the bacterium were correlated with protection. In the present study, the proteins, to which these antibodies were specific for, were identified. Fifteen proteins of the bacterium were identified, and based on known function of homologous proteins in other bacterial pathogens, antibodies specific for the identified proteins are likely important for protective immunity against F. psychrophilum. This work increases the understanding of the protective humoral immune response of rainbow trout against these distinct molecular mass fractions of F. psychrophilum and provides new potential targets for recombinant protein vaccine development.

Technical Abstract: Flavobacterium psychrophilum is the etiologic agent of bacterial coldwater disease (CWD) and this pathogen has large economic impacts on salmonid aquaculture worldwide. Previously, it was demonstrated that high levels of protection against F. psychrophilum challenge were conferred to rainbow trout, Oncorhynchus mykiss (Walbaum), by immunization with distinct molecular mass fractions of the bacterium and specific antibodies were correlated with protection. In the present study, an immunoproteomic analysis of F. psychrophilum was performed using two-dimensional polyacrylamide gel electrophoresis and western blotting with serum from fish immunized with high and mid-molecular mass fractions of the bacterium. Mass spectrometry was used to determine the protein identity, and 15 immunogenic proteins were positively identified following Mascot searches of the F. psychrophilum genome. Based on known function and immunogenicity of homologous proteins in other bacterial pathogens, antibodies specific for several of the identified proteins may be important for protective immunity from CWD. These include outer membrane protein OmpA (P60), trigger factor, ClpB, elongation factor G, gliding motility protein GldN, and a conserved hypothetical protein. This work increases the understanding of the protective humoral immune response of rainbow trout against these distinct molecular mass fractions of F. psychrophilum and provides new potential targets for recombinant protein vaccine development.