Enhancement of protective immunity in European eel (<italic>Anguilla anguilla</italic>) against <italic>Aeromonas hydrophila</italic> and <italic>Aeromonas sobria</italic> by a recombinant <italic>Aeromonas</italic> outer membrane protein

Abstract

To develop a vaccine, which can simultaneously prevent the diseases caused by various pathogenic bacteria in fish, we try to find a conserved outer membrane protein (OMP) antigen from different bacterial pathogens. In this study, an OMP fragment of 747 bp (named as Omp-G), which was highly conserved in seven Aeromonas OMP sequences from the NCBI database, was amplified by PCR from one Aeromonas sobria strain (B10) and two Aeromonas hydrophila strains (B27 and B33) with the designed specific primers. The sequence was cloned into pGEX-2T (6 3 His-tag) vector, expressed in Escherichia coli system, and then the recombinant protein (named as rOmp-G) was purified with nickel chelating affinity chromatography. The purified rOmp-G showed a good immunogenicity in rabbits and well-conserved characteristics in these three pathogens by enzyme-linked immunosorbed assay. Furthermore, the rOmp-G also showed good immunogenicity in eels (Anguilla anguilla) for eliciting significantly increased specific antibodies (P < 0.01), and providing higher protection efficiencies (P < 0.05) after the pathogens challenge. The values of the relative percent survival in eels were 70% and 50% for two A. hydrophila strain challenge, and 75% for A. sobria strain challenge. This is the first report of a potential vaccination in eels that simultaneously provide protectiveness against different Aeromonas pathogens with a conserved partial OMP.

A novel recombinant bivalent outer membrane protein of Vibrio vulnificus and Aeromonas hydrophila as a vaccine antigen of American eel (Anguilla rostrata)

“…# # and # indicate significant differences at P < 0.01 and P < 0.05 were found between two treating groups. protective effect to immunized European eels [16,18]. In this study, a bivalent OMP of V. vulnificus (OmpU) and A. hydrophila (Omp porin Ⅱ) were successfully expressed and purified and the molecular masses (82.2kD) of this recombinant protein revealed by SDS-PAGE were in agreement with computer calculation.…”

“…In this study, a bivalent OMP of V. vulnificus (OmpU) and A. hydrophila (Omp porin Ⅱ) were successfully expressed and purified and the molecular masses (82.2kD) of this recombinant protein revealed by SDS-PAGE were in agreement with computer calculation. Different expressed Omps or extracted natural Omps of bacterial pathogens generally had good immunogenicity [16,17,29], but so far, there were not any reports on the immunogenicity and protective effect of an expressed bivalent OMP from two above-mentioned pathogens. Therefore, we studied the immunogenicity of the bivalent expressed OMP from two major pathogens (V. vulnificus and A. hydrophila) in aquaculture [30,31] to detect the immunogenicity of the bivalent OMP.…”

Aeromonas Flagella and Colonisation Mechanisms

“…OmpW from A. hydrophila is highly immunogenic in common carp and so may be useful for aquaculture disease management (Maiti, Raghunath, & Karunasagar, 2009;Maiti, Shetty, Shekar, Karunasagar, & Karunasagar, 2012). In addition, the immunogenic response to OmpG (another highly conserved OMP in aeromonads) in European eels was found to provide some protection against A. hydrophila and A. sobria (Guan, Xiong, Huang, & Guo, 2011). With respect to OMPs in psychrophilic aeromonads, iron-regulated proteins (IR-OMPs) present on the A. salmonicida cell surface that are thought to be potentially involved in virulence (Ebanks, Dacanay, Goguen, Pinto, & Ross, 2004;Ebanks, Goguen, McKinnon, Pinto, & Ross, 2005).…”

“…For example, Omp48 and OmpW can be used for Aeromonas detection due to their widespread nature and OmpTS for the identification of virulent strains as it is commonly found decorating clinical isolates (Guan et al, 2011;Khushiramani, Girisha, Bhowmick, Karunasagar, & Karunasagar, 2008).…”

Recombinant outer membrane protein C of Aeromonas hydrophila elicits mixed immune response and generates agglutinating antibodies

“…Deletion or mutation of the OmpR and OmpR-dependent genes resulted in avirulent Salmonella typhimurium, respectively, rendered the bacteria avirulent [13,14]. Vaccination with the OMPs of various organisms has been shown to provide protection in host upon challenge with many pathogenic bacteria including A. hydrophila [15][16][17]. These studies indicate that vaccine preparations employing porins/OMPs elicit strong immunogenic reactions, directing the generation of antibodies and humoral immune response to prevent the further infection.…”