The N-Terminal Domain of RTX Toxin ApxI of
            <i>Actinobacillus pleuropneumoniae</i>
            Elicits Protective Immunity in Mice

Seah, June-Nam; Frey, Joachim; Kwang, Jimmy

doi:10.1128/iai.70.11.6464-6467.2002

Cited by 34 publications

(29 citation statements)

References 30 publications

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“…The identification of GtxA, FlfA and Gab_2156 by ELISA further supports the predictive potential and importance of this screening approach, where particularly the Nterminal part of the GtxA-N elicited an extremely high antibody response in comparison to the remaining 26 proteins investigated (Figure 1 and Table 3), thereby suggesting that this part of the protein is particularly promising as a vaccine candidate. This suggestion is supported by a previous study by [63], demonstrating the protective potential of the N-terminal portion of the RTX protein, ApxI, against infections caused by Actinobacillus pleuropneumoniae.…”

Section: Discussionsupporting

confidence: 76%

In silico prediction of

Bager

Kudirkienė

Piedade

et al. 2014

Vet Res

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The Gram-negative bacterium Gallibacterium anatis is a major cause of salpingitis and peritonitis in commercial egg-layers, leading to reduced egg production and increased mortality. Unfortunately, widespread multidrug resistance and antigenic diversity makes it difficult to control infections and novel prevention strategies are urgently needed. In this study, a pan-genomic reverse vaccinology (RV) approach was used to identify potential vaccine candidates. Firstly, the genomes of 10 selected Gallibacterium strains were analyzed and proteins selected on the following criteria; predicted surface-exposure or secretion, none or one transmembrane helix (TMH), and presence in six or more of the 10 genomes. In total, 42 proteins were selected. The genes encoding 27 of these proteins were successfully cloned in Escherichia coli and the proteins expressed and purified. To reduce the number of vaccine candidates for in vivo testing, each of the purified recombinant proteins was screened by ELISA for their ability to elicit a significant serological response with serum from chickens that had been infected with G. anatis. Additionally, an in silico prediction of the protective potential was carried out based on a protein property prediction method. Of the 27 proteins, two novel putative immunogens were identified; Gab_1309 and Gab_2312. Moreover, three previously characterized virulence factors; GtxA, FlfA and Gab_2156, were identified. Thus, by combining the pan-genomic RV approach with subsequent in vitro and in silico screening, we have narrowed down the pan-proteome of G. anatis to five vaccine candidates. Importantly, preliminary immunization trials indicated an in vivo protective potential of GtxA-N, FlfA and Gab_1309.

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Section: Discussionsupporting

confidence: 76%

In silico prediction of

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Kudirkienė

Piedade

et al. 2014

Vet Res

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“…The same pigs were also negative by all other assays. As the serovar 14 isolate (strain 3906) used in the current study has been previously characterized and is known to express ApxI, 33,41 this may indicate problems with the inoculum production (viability, antigenic load) or inoculation procedure. Interestingly, both pigs infected with serovar 12 were seropositive for ApxI in the study.…”

Section: Discussionmentioning

confidence: 99%

Evaluation of diagnostic assays for the serological detection ofActinobacillus pleuropneumoniaeon samples of known or unknown exposure

et al. 2013

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Abstract. Accurate diagnosis of exposure to Actinobacillus pleuropneumoniae is important for maintaining negative farms. In the present study, the ability of a dual-plate complement fixation (CF) assay and 3 commercially available enzymelinked immunosorbent assays (ELISAs; quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3) in detecting serological evidence of A. pleuropneumoniae exposure was compared using serum samples of experimentally infected or vaccinated pigs, or field samples from the United States. Forty-two pigs were divided into groups of 2 pigs and were inoculated with 1 of 15 A. pleuropneumoniae strains representing all known serovars of A. pleuropneumoniae, or with Actinobacillus suis, or were vaccinated with a bacterin containing A. pleuropneumoniae serovar 1, 3, 5, or 7. Serum samples collected at the day of inoculation or vaccination and 7, 14, 21, and 28 days later were used to compare the assays. On samples from experimentally infected pigs, the dual-plate CF assay, quad-plate ELISA-1, single-plate ELISA-2, and single-plate ELISA-3 had sensitivities of 0.46, 0.74, 0.13, and 0.13 and specificities of 0.90, 1.0, 1.0, and 1.0, respectively. Vaccinated pigs were identified only by the dual-plate CF assay and the quad-plate ELISA-1. In addition, 90 serum samples with unknown A. pleuropneumoniae exposure collected under field conditions were tested with all assays. The agreement of the 4 assays on field samples was slight to fair. While several assays are available for demonstration of A. pleuropneumoniae exposure, differences in assay targets complicate test choices. Decisions on which assay or combination of assays to use depend on the specific reasons for running the assays.

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“…Genes for active RTX toxins comprise rtxC, A, B, and D, 8) which encodes the post-translational activator, the structural toxin, and proteins required for secretion of the activated toxin respectively. 2,3,9) RtxB and RtxD are required for the secretion of a functional toxin complex composed of RtxA and RtxC. The structural toxin RtxA is initially synthesized in an inactive form and is then processed to become a functional toxin through acylation and complex formation with RtxC.…”

mentioning

confidence: 99%

“…To synthesize active Apx toxins, the activity of four genes, apxC, apxA, apxB, and apxD, is required. 2,3,9) Most A. pleuropneumoniae serotypes produce one or two exotoxins among the ApxI, II, and III proteins. Both ApxI and ApxII of A. pleuropneumoniae are essential for full virulence and the development of clinical signs and typical lung lesions.…”

mentioning

confidence: 99%

Surface-Displayed Expression of a Neutralizing Epitope of ApxIIA Exotoxin inSaccharomyces cerevisiaeand Oral Administration of It for Protective Immune Responses against Challenge byActinobacillus pleuropneumoniae

Kim¹,

Jung²,

Eom³

et al. 2010

Bioscience, Biotechnology, and Biochemistry

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A neutralizing epitope fragment of ApxIIA toxin (ApxIIA#5) of the Korean Actinobacillus pleuropneumoniae serotype 2 strain was expressed and immobilized on the cell surface of Saccharomyces cerevisiae for efficient vaccine development. Expression of ApxIIA#5 was confirmed by Western blot analysis using cell-wall proteins, and the surface display of ApxIIA#5 was further visualized under confocal microscopy. Quantitative ELISA revealed that the recombinant ApxIIA#5 directed to the cell surface consisted of approximately 16% cell-wall proteins, estimated to be 35 mg of ApxIIA#5 protein per liter of cultured cells. An immunoassay revealed that antigen-specific antibodies against ApxIIA#5 were present in the sera of mice fed recombinant ApxIIA#5-expressing yeast, but not in mice fed the wild-type nor the vector-only transformant. Moreover, the mice fed the recombinant epitope-expressing yeast were protected from injection of a lethal dose of A. pleuropneumoniae.

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The N-Terminal Domain of RTX Toxin ApxI of Actinobacillus pleuropneumoniae Elicits Protective Immunity in Mice

Cited by 34 publications

References 30 publications

In silico prediction of

In silico prediction of

Evaluation of diagnostic assays for the serological detection ofActinobacillus pleuropneumoniaeon samples of known or unknown exposure

Surface-Displayed Expression of a Neutralizing Epitope of ApxIIA Exotoxin inSaccharomyces cerevisiaeand Oral Administration of It for Protective Immune Responses against Challenge byActinobacillus pleuropneumoniae

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