Immunological characterization of a bacterial protein isolated from salmonid fish naturally infected with Piscirickettsia salmonis

• Published in: Vaccine 2007-03, Vol.25 (11), p.2095-2102
• Main Authors: Marshall, Sergio H, Conejeros, Pablo, Zahr, Marcela, Olivares, Jorge, Gómez, Fernando, Cataldo, Patricio, Henríquez, Vitalia
• Format: Article
• Language: English
• Subjects: Allergy and Immunology; Amino Acid Sequence; Animals; Antibodies, Bacterial - blood; Applied microbiology; Bacterial Proteins - chemistry; Bacterial Proteins - genetics; Bacterial Proteins - immunology; Bacterial Proteins - isolation & purification; Bacteriology; Biological and medical sciences; Blotting, Western; Caulobacter - genetics; Caulobacter crescentus; Cloning, Molecular; DNA, Bacterial - chemistry; DNA, Bacterial - genetics; Electrophoresis, Gel, Two-Dimensional; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Fish Diseases - immunology; Fish Diseases - microbiology; Fundamental and applied biological sciences. Psychology; Gene Expression; Heat-Shock Proteins - immunology; Heat-Shock Proteins - isolation & purification; Immunogenicity; In vivo isolated protein; Intracellular bacterial pathogen; Microbiology; Miscellaneous; Molecular Sequence Data; Molecular Weight; Oncorhynchus kisutch; Piscirickettsia - immunology; Piscirickettsia salmonis; Piscirickettsiaceae Infections - immunology; Piscirickettsiaceae Infections - microbiology; Piscirickettsiaceae Infections - veterinary; Potential vaccine; Rickettsia; Salmonidae; Sequence Analysis, DNA; Sequence Homology, Amino Acid; Vaccines, antisera, therapeutical immunoglobulins and monoclonal antibodies (general aspects)
• ISSN: 0264-410X; 1873-2518
• DOI: 10.1016/j.vaccine.2006.11.035

Abstract The Salmon Rickettsia syndrome (SRS) remains a major infectious disease in the Chilean aquaculture. A limited number of Piscirickettsia salmonis proteins have been characterized so far for their use as potential candidates for vaccines studies. In this study, we identified and expressed a highly immunogenic protein of P. salmonis extracted by selective hydrophobicity from crude-cell macerates of naturally infected salmonid fish. One and two-D PAGE gels followed by Western blot analysis with a battery of polyclonal anti- P. salmonis antibodies have allowed the isolation of the target protein. Basic local alignment search (BLAST) done after partial sequencing of the pure protein identified it as a member of the heat-shock protein (HSP) family of prokaryotes. The protein, named ChaPs, was cloned as a single open reading frame encoding 545 amino acid residues with a predicted molecular mass of 57.3 kDa. The amplicon representing the entire novel gene was expressed in vitro in different heterologous systems: the PurePro Caulobacter crescentus expression system from where most of the characterization was attained, and also in the Escherichia coli BL-21 CodonPlus model for commercially potential purposes. The immunologic potential of ChaPs was determined with serum from naturally infected fish.