Serotyping<i>Actinobacillus Pleuropneumoniae</i>by the use of Monoclonal Antibodies

Lacouture, Sonia; Mittal, K. R.; Jacques, Mario; Gottschalk, Marcelo

doi:10.1177/104063879700900324

Cited by 17 publications

(17 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The isolate presented a clear reaction with both polyclonal antibodies against serotype 1 (18) and monoclonal antibodies against the CPS of serotype 1 (15). It also exhibited a PCR profile of the Apx toxins (positive for ApxI, ApxII, and ApxIV) expected for serotype 1 (6).…”

mentioning

confidence: 92%

Isolation of an Atypical Strain ofActinobacillus pleuropneumoniaeSerotype 1 with a Truncated Lipopolysaccharide Outer Core and No O-Antigen

et al. 2005

Self Cite

View full text Add to dashboard Cite

A field isolate of Actinobacillus pleuropneumoniae, the causative agent of porcine fibrinohemorrhagic necrotizing pleuropneumonia, was sent to the diagnostic laboratory for serotyping. The isolate presented a clear reaction, with both polyclonal antibodies against serotype 1 and monoclonal antibodies against the capsular polysaccharide of serotype 1. It also exhibited a PCR profile of Apx toxins expected for serotype 1. The isolate, however, failed to react with monoclonal antibodies against the O-antigen of serotype 1 lipopolysaccharide (LPS), suggesting a rough phenotype. The lipid A-core region of the isolate migrated faster than the corresponding region of the serotype 1 reference strain S4074 by Tricine-sodium dodecyl sulfate-polyacrylamide gel electrophoresis, suggesting the presence of a truncated core. Sugar analysis and mass spectrometry analysis of the O-deacylated LPS from the field isolate were consistent with the absence of O-antigen and truncation of the outer core compared to the wild-type reference strain. Experimental infection of pigs confirmed the virulence of the isolate. This is the first report of an isolate of A. pleuropneumoniae serotype 1 with a truncated outer core and a rough LPS phenotype. Veterinary diagnostic laboratories should be vigilant, since infections caused by such an isolate will not be detected by serological tests based on LPS O-antigen.Actinobacillus pleuropneumoniae is the etiologic agent of porcine pleuropneumonia, a highly contagious respiratory disease with major economic implications for the swine industry worldwide (27). Twelve serotypes of NAD-dependent A. pleuropneumoniae have been recognized based on capsular polysaccharide (CPS) and lipopolysaccharide (LPS) antigens (19), and an additional serotype has recently been proposed by Blackall et al. (2). Two additional serotypes of NAD-independent A. pleuropneumoniae have been reported (20). In North America, serotypes 1, 5, and 7 are the most prevalent serotypes recovered from diseased animals (4).Infection by A. pleuropneumoniae is a multifactorial process governed by many virulence factors acting alone or in concert and by host susceptibility. Several virulence factors, such as CPS, LPS, outer membrane proteins, and Apx toxins, have already been identified (3, 5, 10). Studies by our group have focused on surface polysaccharides, namely, CPS and LPS, of A. pleuropneumoniae (4, 12). We have previously shown that the LPS molecule plays an important role in adherence of the bacterium to porcine respiratory tract cells and mucus (11). LPS molecules are a major constituent of outer membranes of gram-negative bacteria. They consist of a polysaccharide and a lipid moiety. The polysaccharide part is composed of a core region, which is an oligosaccharide containing 3-deoxy-Dmanno-2-octulosonic acid (Kdo), and the O antigen, a polysaccharide chain consisting of repeated units. We have generated rough LPS mutants as well as core LPS mutants by using transposon mutagenesis and showed that the core region of LPS seems to play a...

show abstract

mentioning

confidence: 92%

Isolation of an Atypical Strain ofActinobacillus pleuropneumoniaeSerotype 1 with a Truncated Lipopolysaccharide Outer Core and No O-Antigen

et al. 2005

Self Cite

View full text Add to dashboard Cite

show abstract

“…The use of CPS-and O-chain LPS-directed monoclonal an- Received for publication June 17, 1999. tibodies has proved to be a superior tool for differentiating several of these isolates. [9][10][11]16,21 The characterization of 3 selected A. pleuropneumoniae atypical isolates antigenically related to serotypes 1 and 7 is reported in the present study. In 1997, isolations of A. pleuropneumoniae were attempted from tonsils of clinically healthy animals in 3 different herds of pigs located in Quebec, Canada, using a recently described immunomagnetic method.…”

mentioning

confidence: 96%

“…[9][10][11]16,21 The characterization of 3 selected A. pleuropneumoniae atypical isolates antigenically related to serotypes 1 and 7 is reported in the present study.…”

mentioning

confidence: 96%

“…In fact, when using serotype-specific monoclonal antibodies, no cross-reactions could be detected between serotypes 1 and 7 isolates. [9][10][11] In the case of the 3 isolates tested in this study, it was speculated that the observed cross-reactions were strong enough to be caused by serotype-specific antigens. 414 ) of approximately 1.0 in an indirect ELISA using the appropriate strain 10 was preincubated for 2 hours at 37 C. This was followed by an overnight incubation at 4 C (serotype 7-specific MAbs) or a 20-minute room temperature incubation (serotype 1-specific MAbs), with whole-cell antigens 15 of A. pleuropneumoniae-positive control strains (reference strains 4074 and WF83 for serotypes 1 and 7, respectively), negative control strain (A. pleuropneumoniae serotype 5b, strain 81-781 9 ) or isolates 1B, 27E, or 26B.…”

mentioning

confidence: 99%

“…The supernatants were tested in an indirect ELISA using a whole-cell antigen of the corresponding strain used for the production of each MAb. [9][10][11] Results indicate that isolates 27E and 1B could inhibit the reactivities of all MAbs at different levels ( Further characterization of these atypical isolates included genetic fingerprinting by randomly amplified polymorphic DNA (RAPD) analysis, toxin gene profiling, and virulence testing in mice and pigs. The RAPD fingerprinting was carried out as previously described 3 using primers OPB7, OPB11, d and #17 e .…”

mentioning

confidence: 99%

See 2 more Smart Citations

AtypicalActinobacillus PleuropneumoniaeIsolates That Share Antigenic Determinants with Both Serotypes 1 and 7

et al. 2000

View full text Add to dashboard Cite

Abstract. In the present study, the characterization of 3 atypical isolates of Actinobacillus pleuropneumoniae is presented. Two isolates (1B and 27E) showed positive reactions in coagglutination, immunodiffusion, and indirect hemagglutination tests for serotypes 1 and 7, whereas the third isolate (26B) reacted with antisera to serotypes 1, 4, and 7. These atypical isolates of A. pleuropneumoniae possessed a capsular polysaccharide (CPS) antigenically related to serotype 1 as well as an O-chain lipopolysaccharide antigenically related to serotype 7 or to serotypes 4 and 7, as shown by the use of monoclonal antibodies. Results of toxin profile and virulence assays for mice and pigs showed them to be more related to A. pleuropneumoniae serotype 7 field isolates. All 3 isolates induced antibodies mainly against serotype 7/4 O-long-chain lipopolysaccharide (LC-LPS) and, to a lesser extent, to the CPS of serotype 1, in experimentally infected pigs. Diagnostic laboratories that use a LC-LPS-based enzyme-linked immunosorbent assay (ELISA) for serodiagnosis of A. pleuropneumoniae infection in swine would probably diagnose herds infected with these atypical isolates as being infected by A. pleuropneumoniae serotypes 7 or 4, whereas those that use a CPS-based ELISA would probably consider them as infected by A. pleuropneumoniae serotype 1.Actinobacillus pleuropneumoniae is associated with swine pleuropneumonia, an important contagious swine disease found throughout the world. Until now, a total of 12 nicotinamide adenine dinucleotide (NAD)-dependent serotypes have been described; serotypes 1, 5, and 7 are most commonly isolated from clinical cases of pleuropneumonia in North America. 14 Inconsistent and contradictory results are sometimes found when serotyping field isolates. 1 Serotype-specific antigens of A. pleuropneumoniae are present mainly in the capsular polysaccharide (CPS) 17,19 but, for some serotypes, these antigens are also located in the O-chain of the lipopolysaccharide (LPS). 19 Actinobacillus pleuropneumoniae also possesses antigens that are shared by several serotypes. For example, cross-reactivity has been observed among isolates belonging to serotypes 1, 9, and 11; 3, 6, and 8, and 4 and 7. [12][13][14]16,21 Most of these common epitopes are located in the LPS. Recently, common O-chain LPS epitopes have been reported between A. pleuropneumoniae serotype 7 and Actinobacillus lignieresii. 11 A scheme using both CPS and LPS-O antigens has been proposed for serotyping A. pleuropneumoniae. 16,19,21 Using this scheme, serotypes 1, 9, and 11 would be designated as serotypes K1:O1, K1:O11, and K9:O9; serotypes 4 and 7 as serotypes K4:O4 and K7:O4; and serotypes 3, 6, and 8 as K3:O3, K3:O6, and K3:O8. This nomenclature follows that for serotyping members of the family Enterobacteriaceae. The use of CPS-and O-chain LPS-directed monoclonal an- Received for publication June 17, 1999. tibodies has proved to be a superior tool for differentiating several of these isolates. [9][10][11]16,21 The characterization of ...

show abstract