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Phage Display Detection of Mimotopes that Are Shared Epitopes of Clinically and Epidemiologically Relevant Enterobacteria. Microorganisms 2020; 8:microorganisms8050780. [PMID: 32455888 PMCID: PMC7285282 DOI: 10.3390/microorganisms8050780] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2020] [Revised: 05/12/2020] [Accepted: 05/19/2020] [Indexed: 11/18/2022] Open
Abstract
Background: Escherichia coli and Salmonella are etiologic agents of intestinal infections. A previous study showed the presence of shared epitopes between lipopolysaccharides (LPSs) of E. coli O157 and Salmonella. Aim: Using phage display, the aim of this study is to identify mimotopes of shared epitopes in different enterobacterial LPSs. Methods: We use anti-LPS IgG from E. coli O157 and Salmonella to select peptide mimotopes of the M13 phage. The amino acid sequence of the mimotopes is used to synthesize peptides, which are in turn used to immunize rabbits. The antibody response of the resulting sera against the LPSs and synthetic peptides (SPs) is analyzed by ELISA and by Western blot assays, indicating that LPS sites are recognized by the same antibody. In a complementary test, the reactions of human serum samples obtained from the general population against the SPs and LPSs are also analyzed. Results: From the last biopanning phase, sixty phagotopes are selected. The analysis of the peptide mimotope amino acid sequences shows that in 4 of them the S/N/A/PF motif is a common sequence. Antibodies from the sera of immunized rabbits with SP287/3, SP459/1, SP308/3, and SP073/14 react against both their own peptide and the different LPSs. The Western blot test shows a sera reaction against both the lateral chains and the cores of the LPSs. The analysis of the human sera shows a response against the SPs and LPSs. Conclusion: The designed synthetic peptides are mimotopes of LPS epitopes of Salmonella and E. coli that possess immunogenic capacity. These mimotopes could be considered for use in the design of vaccines against both enterobacteria.
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Whitfield C, Kaniuk N, Frirdich E. Molecular insights into the assembly and diversity of the outer core oligosaccharide in lipopolysaccharides from Escherichia coli and Salmonella. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519030090040501] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In the Enterobacteriaceae, the core oligosaccharide provides the junction between the highly conserved lipid A and the remarkably diverse polysaccharide O antigen. The basic structure of the inner (lipid A-proximal) core is well conserved, perhaps reflecting constraints imposed by its involvement in the structural integrity of the outer membrane. However, non-stoichiometric modifications do create some structural variants. The outer core may show more variation. Efforts to develop immunoprophylactic strategies based on the core oligosaccharide require a detailed understanding of core immunochemistry, the accessibility of specific epitopes in the LPS, and the distribution of specific structures within natural populations. The availability of sequences for the waa (core biosynthesis) loci and functional data for the gene products provide a molecular basis for the known structural diversity in Escherichia coli and Salmonella core oligosaccharide. Surveys of waa-locus organization have established the distribution of these core types in natural populations and have identified genetic variants that provide candidates for additional novel structures.
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Affiliation(s)
- Chris Whitfield
- Department of Microbiology, University of Guelph, Guelph, Ontario, Canada,
| | - Natalia Kaniuk
- Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
| | - Emilisa Frirdich
- Department of Microbiology, University of Guelph, Guelph, Ontario, Canada
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Pathogen-free screening of bacteria-specific hybridomas for selecting high-quality monoclonal antibodies against pathogen bacteria as illustrated for Legionella pneumophila. J Immunol Methods 2013; 391:81-94. [PMID: 23454033 DOI: 10.1016/j.jim.2013.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Revised: 02/19/2013] [Accepted: 02/21/2013] [Indexed: 11/20/2022]
Abstract
Antibodies are potent biological tools increasingly used as detection, diagnostic and therapeutic reagents. Many technological advances have optimized and facilitated production and screening of monoclonal antibodies. We report here an original method to screen for antibodies targeting biosafety level 2 or 3 pathogens without the fastidious handling inherent to pathogen use. A double ELISA screening was performed using as coated antigen transformed Escherichia coli expressing at its surface a protein specific to the pathogenic bacteria versus control untransformed E. coli. This method was applied to Legionella, using the surface-exposed Mip protein (macrophage infectivity potentiator). This screening proved to be an excellent means of selecting mAbs that bind Legionella pneumophila 1 surface-exposed Mip protein. This method also appears more biologically relevant than screening using the recombinant Mip protein alone and less tedious than a test performed directly on Legionella bacteria. We obtained 21 mAbs that bind strongly to L. pneumophila serogroups 1 to 13, and we validated their use in a rapid ELISA (performed in 4.5 h) and an immunochromatographic test (20 min).
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Ronholm J, Zhang Z, Cao X, Lin M. Monoclonal antibodies to lipopolysaccharide antigens of Salmonella enterica serotype Typhimurium DT104. Hybridoma (Larchmt) 2011; 30:43-52. [PMID: 21466285 DOI: 10.1089/hyb.2010.0066] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Salmonella enterica subsp. enterica serotype Typhimurium is one of the major causative agents of human gastroenteritis. Here we raised a panel of 45 monoclonal antibodies (MAbs) against ser. Typhimurium DT104 by immunizing mice with formalin-killed bacteria and demonstrated that all the MAbs recognized the bacterial lipopolysaccharide (LPS) antigen. These MAbs were specific for group O:4 Salmonella with very little or no cross-reactivity with other closely related bacteria and were able to bind to the cell surface of live bacterial cells, making them potential candidates for capture and concentration of the pathogen in food and water samples. Epitope characterization revealed that the O:5 antigen present in the LPS of some serogroup 4 Salmonella is the critical factor for the binding of these MAbs to LPS. This study has provided some insights into the structure of the Salmonella LPS and its influence on the antigenicity of LPS.
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Affiliation(s)
- Jennifer Ronholm
- Canadian Food Inspection Agency, Ottawa Laboratory Fallowfield, Ottawa, Ontario, Canada
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Choi D, Tsang RS, Ng MH. Sandwich capture ELISA by a murine monoclonal antibody against a genus-specific LPS epitope for the detection of different common serotypes of salmonellas. ACTA ACUST UNITED AC 2008; 72:134-8. [PMID: 1372888 DOI: 10.1111/j.1365-2672.1992.tb01814.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
A sandwich capture ELISA based on a murine monoclonal antibody against a genus-specific epitope in the outer core region of the Salmonella lipopolysaccharide is described for the detection of different common serotypes of salmonellas. Four h broth cultures of seven standard and 24 wild strains of salmonellas were all detected by the capture ELISA while overnight broth cultures of 21 non-salmonella standard strains were all negative. The capture ELISA detected 1 ng/ml of Ra lipopolysaccharide, 10(6)/ml of a smooth wild strain of Salm. typhimurium, and 1120 cells of Salm. heidelberg after enrichment culture for 4 h.
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Affiliation(s)
- D Choi
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital Compound
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6
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Mazumdar SD, Hartmann M, Kämpfer P, Keusgen M. Rapid method for detection of Salmonella in milk by surface plasmon resonance (SPR). Biosens Bioelectron 2007; 22:2040-6. [PMID: 17079127 DOI: 10.1016/j.bios.2006.09.004] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2006] [Revised: 08/02/2006] [Accepted: 09/01/2006] [Indexed: 11/20/2022]
Abstract
The Plasmonic surface plasmon resonance (SPR) device was used to develop a rapid, simple and specific immunoassay for detection of Salmonella in milk. Rapid detection of Salmonella contamination is a major challenge for the food industry. Salmonella contamination is well known in all foods including pasteurised milk. The SPR assay was developed as a sandwich model using a polyclonal antibody against Salmonella as capture and detection antibody. Milk spiked with Salmonella typhimurium cells, killed by thimerosal (1%, w/w) treatment was used. Using the Plasmonic SPR assay it was possible to detect S. typhimurium down to a concentration of 1.25 x 10(5) cells ml(-1) in both milk and buffer system. The results obtained are comparable with existing, approved rapid Salmonella detection techniques. No negative effects on the sensitivity of the assay are encountered due to the milk matrix. Hence, no sample preparation or clean-up steps are required. The sample volume requirement for the assay is only 10 microl. Using the assay S. typhimurium was detected in milk within 1h, whereas the cultural techniques require 3-4 days for presumptive positive isolates and further time for confirmation. The rapid tests require at least 24h for the results. The Plasmonic SPR device operates on the Kretschmann configuration and is a cuvette-based system with the advantage of having eight channels on one single SPR chip.
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Affiliation(s)
- Saikat Datta Mazumdar
- Institute for Pharmaceutical Chemistry, Philipps-Universität Marburg, Marbacher Weg 6, D-35032 Marburg, Germany
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Kaniuk NA, Monteiro MA, Parker CT, Whitfield C. Molecular diversity of the genetic loci responsible for lipopolysaccharide core oligosaccharide assembly within the genus Salmonella. Mol Microbiol 2002; 46:1305-18. [PMID: 12453217 DOI: 10.1046/j.1365-2958.2002.03243.x] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The waa locus on the chromosome of Salmonella enterica encodes enzymes involved in the assembly of the core oligosaccharide region of the lipopolysaccharide (LPS) molecule. To date, there are two known core structures in Salmonella, represented by serovars Typhimurium (subspecies I) and Arizonae (subspecies IIIA). The waa locus for serovar Typhimurium has been characterized. Here, the corresponding locus from serovar Arizonae is described, and the molecular basis for the distinctive structures is established. Eleven of the 13 open reading frames (ORFs) are shared by the two loci and encode conserved proteins of known function. Two polymorphic regions distinguish the waa loci. One involves the waaK gene, the product of which adds a terminal alpha-1,2-linked N-acetylglucosamine residue that characterizes the serovar Typhimurium core oligosaccharide. There is an extensive internal deletion within waaK of serovar Arizonae. The serovar Arizonae locus contains a novel ORF (waaH) between the waaB and waaP genes. Structural analyses and in vitro glycosyltransferase assays identified WaaH as the UDP-glucose:(glucosyl) LPS alpha-1,2-glucosyltransferase responsible for the addition of the characteristic terminal glucose residue found in serovar Arizonae. Isolates comprising the Salmonella Reference Collections, SARC (representing the eight subspecies of S. enterica) and SARB (representing subspecies I), were examined to assess the distribution of the waa locus polymorphic regions in natural populations. These comparative studies identified additional waa locus polymorphisms, shedding light on the genetic basis for diversity in the LPS core oligosaccharides of Salmonella isolates and identifying potential sources of further novel LPS structures.
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Affiliation(s)
- Natalia A Kaniuk
- Department of Microbiology, University of Guelph, Guelph, ON, Canada, N1G 2W1
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Olsthoorn MM, Petersen BO, Schlecht S, Haverkamp J, Bock K, Thomas-Oates JE, Holst O. Identification of a novel core type in Salmonella lipopolysaccharide. Complete structural analysis of the core region of the lipopolysaccharide from Salmonella enterica sv. Arizonae O62. J Biol Chem 1998; 273:3817-29. [PMID: 9461562 DOI: 10.1074/jbc.273.7.3817] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
For the first time, the complete structure of a lipopolysaccharide (LPS) core region from Salmonella enterica has been identified that is different from the Ra core type generally thought to be present in all Salmonella LPS. The LPSs from two rough mutants and the smooth form of S. enterica sv. Arizonae IIIa O62, which all failed to react with an Ra core type-specific monoclonal antibody and were resistant to phage FO1, were analyzed after chemical modification using monosaccharide analysis, mass spectrometry, and NMR spectroscopy. In the novel core type, the terminal D-GlcNAc residue present in the Ra core type, is replaced by a D-Glc residue. The O-specific polysaccharide is alpha1-->4-linked to the second distal Glc residue of the core. Furthermore, phosphoryl substituents attached to O-4 of L-glycero-D-manno-heptose (Hep) I and II were identified as 2-aminoethyl diphosphate (on Hep I) and phosphate (Hep II). [structure: see text] Abbreviations in Structure I are as follows: Hepp, L-glycero-D-manno-heptopyranose; Kdo, 3-deoxy-D-manno-oct-2-ulopyranosonic acid; PPEA, 2-aminoethyl diphosphate; R, O-specific polysaccharide. The presence of this novel core type in LPS of S. enterica should be taken into account in the development of a general antibody-based diagnostic system for Salmonella.
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Affiliation(s)
- M M Olsthoorn
- Department of Mass Spectrometry, Bijvoet Center for Biomolecular Research, Utrecht University, NL-3508 TB Utrecht, The Netherlands
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Tsang RS, Nielsen KH, Henning DM, Poppe C, Khakhria R, Woodward DL, Johnson WM. Screening for Salmonella with a murine monoclonal antibody M105 detects both Felix O1 bacteriophage sensitive and resistant Salmonella strains. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1997; 286:23-32. [PMID: 9241797 DOI: 10.1016/s0934-8840(97)80071-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Ten Felix O1 (FO1) bacteriophage sensitive Salmonella strains as well as their phage resistant derivates together with 39 strains of FO1-resistant Salmonella were tested for their reactivities with a murine monoclonal antibody, M105, by indirect whole cell and competitive ELISA. All FO1 phage sensitive and 48 of the 49 FO1-resistant Salmonella strains were found to react with M105. The single Salmonella strain not reacting with M105 was a FO1 resistant derivative selected by exposing the sensitive parent strain to the phage. This M105-negative and FO1-resistant strain was also found to be a rough mutant without O-antigens and possibly lacks the terminal LPS core sugars which form the M105 reactive epitope.
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Affiliation(s)
- R S Tsang
- National Laboratory for Enteric Pathogens, Bureau of Microbiology, Health Canada.
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Tan S, Gyles CL, Wilkie BN. Comparison of an LPS-specific competitive ELISA with a motility enrichment culture method (MSRV) for detection of Salmonella typhimurium and S. enteritidis in chickens. Vet Microbiol 1997; 56:79-86. [PMID: 9228684 DOI: 10.1016/s0378-1135(96)01346-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We report here evaluation of a competitive enzyme-linked immunosorbent assay (c-ELISA) for detection of Salmonella spp. in chicken organs and faeces. The c-ELISA used a monoclonal antibody (MAb), specific for a genus-specific epitope of the outer core oligosaccharide of salmonellae. Salmonella lipopolysaccharide (LPS) in samples competed with Salmonella LPS coated on microtitre plates, for binding to the MAb. Competition reduced binding of the MAb to the LPS on the plate and of the secondary antibody to the MAb hence reducing the chromogenic signal. Stable coating and minimal false positive were achieved by conjugating LPS to poly-L-lysine. The c-ELISA was compared with motility enrichment culture using modified semisolid Rappaport Vassiliadis (MSRV) medium, which detected less than 10(2) CFU/g, and did not allow migration of non-salmonella species. The c-ELISA detected 10(6) CFU of enriched culture or 10(2)-10(3) CFU of Salmonella/g of faeces. Its limit of detection was thus higher than that of MSRV culture and it had a sensitivity of 92.9% and a specificity of 96.7%.
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Affiliation(s)
- S Tan
- Department of Veterinary Microbiology and Immunology, University of Guelph, Ont, Canada.
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Ng SP, Tsui CO, Roberts D, Chau PY, Ng MH. Detection and serogroup differentiation of Salmonella spp. in food within 30 hours by enrichment-immunoassay with a T6 monoclonal antibody capture enzyme-linked immunosorbent assay. Appl Environ Microbiol 1996; 62:2294-302. [PMID: 8779567 PMCID: PMC168010 DOI: 10.1128/aem.62.7.2294-2302.1996] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
We previously described an antigen capture enzyme-linked immunosorbent assay which makes use of monoclonal antibody T6, which recognizes an epitope on the outer core polysaccharide of Salmonella lipopolysaccharide molecules that is common to almost all Salmonella serovars. In this paper, we show that this assay can detect between 10(5) and 10(7) Salmonella cells per ml even in the presence of excess Escherichia coli. A total of 153 of 154 (99%) serogroup A to E strains and 51 of 78 (71%) serogroup F to 67 strains were reactive as determined by this assay. This corresponds to a detection rate of approximately 98% of all salmonellae known to affect humans. None of the 65 strains of non-Salmonella bacteria tested positive. Taking advantage of the O-factor polysaccharides also present on the antigen captured by the immobilized T6 antibody, we showed that 136 of 154 Salmonella serogroup A to E strains (88%) were correctly differentiated according to their serogroups by use of enzyme conjugates of a panel of O-factor-specific monoclonal antibodies. We evaluated this assay for the detection and serogroup differentiation of salmonellae directly from enrichment cultures of simulated food, eggs, pork, and infant formula milk. All 26 samples which had been contaminated with Salmonella spp. were detected by T6 (100% sensitivity), with only one false-positive result from 101 samples not contaminated by Salmonella spp. (99% specificity). The detection time was substantially reduced to between 17 and 29 h, depending on the enrichment methods used. Since there were no false-negative results, we concluded that this enrichment-immunoassay method can afford rapid screening for Salmonella spp. in food samples.
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Affiliation(s)
- S P Ng
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital, Hong Kong.
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TSANG RAYMONDS, NIELSEN KLAUSH, JOHNSON WENDYM. DEVELOPMENT OF AN INDIRECT WHOLE CELL ELISA FOR THE RAPID IDENTIFICATION OF SALMONELLA. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1745-4581.1995.tb00116.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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TSANG RAYMONDS, NIELSEN KLAUSH, BALSEVICIUS SOPHIA, KELLY LINDA, KHAKHRIA RASIK, JOHNSON WENDYM. COMPETITIVE ENZYME IMMUNOASSAY FOR THE RAPID IDENTIFICATION OF SALMONELLA. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1745-4581.1995.tb00096.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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NIELSEN K, TSANG R. COMPARISON of ANALYTICAL SENSITIVITIES of THREE ENZYME IMMUNOASSAY PROCEDURES FOR the DETECTION of SALMONELLA LIPOPOLYSACCHARIDE. ACTA ACUST UNITED AC 1992. [DOI: 10.1111/j.1745-4581.1992.tb00089.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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NIELSEN K, TSANG R, GARCIA M, SURUJBALLI O, NEMEC M. COMPETITIVE ENZYME IMMUNOASSAY FOR the DETECTION of SALMONELLA LIPOPOLYSACCHARIDE. ACTA ACUST UNITED AC 1992. [DOI: 10.1111/j.1745-4581.1992.tb00278.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tsang RS, Schlecht S, Mayer H. Structural differences in the outer core region of lipopolysaccharides derived from members of the genus Salmonella. ZENTRALBLATT FUR BAKTERIOLOGIE : INTERNATIONAL JOURNAL OF MEDICAL MICROBIOLOGY 1992; 276:330-9. [PMID: 1374277 DOI: 10.1016/s0934-8840(11)80539-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Spontaneous and P22-resistant rough mutants, respectively, selected from Salmonella IV (18: z36, z38:-) and S. djakarta (48: z4, z24:-), appeared to lack the epitope recognized by the T6 monoclonal antibody which had been previously shown to correspond to the terminal alpha-1,2-linked N-acetyl-D-glucosamine residue of the Salmonella lipopolysaccharide (LPS) Ra core. LPSs and core oligosaccharides were therefore prepared from these two rough mutants and analysed by chemical and serological methods. Sugar analyses as well as methylation and 13C-NMR studies indicated that rough mutants derived from these two serotypes indeed possessed outer core structures differing from those of the well-characterized Salmonella Ra core. Serological data corroborated the chemical findings. Proposed structures of the outer core regions of these two R-types are presented and the significance of the findings is discussed.
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Affiliation(s)
- R S Tsang
- Department of Microbiology, Queen Mary Hospital Compound, University of Hong Kong
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Todd E, Mackenzie J, Parrington L, Sharpe A, Peterkin P, Diotte M, Gidney M, Nielson K, Fraser A, Rahn K, Tiffin A, Paterson G, Gehle W. Evaluation of Salmonella antisera for an optimum enzyme-linked antibody detection of Salmonella using hydrophobic grid membrane filters. Food Microbiol 1991. [DOI: 10.1016/s0740-0020(05)80005-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tsang RS, Schlecht S, Aleksic S, Chan KH, Chau PY. Lack of the alpha-1,2-linked N-acetyl-D-glucosamine epitope in the outer core structures of lipopolysaccharides from certain O serogroups and subspecies of Salmonella enterica. Res Microbiol 1991; 142:521-33. [PMID: 1719590 DOI: 10.1016/0923-2508(91)90185-d] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A total of 176 strains of Salmonella enterica representing 116 serotypes were tested for the presence of the T6 epitope of the alpha-1,2-linked N-acetyl-D-glucosamine residue by reaction with a murine monoclonal antibody T6 specific for this structure in the Salmonella Ra core lipopolysaccharide (LPS). All 20 serotypes (70 strains) belonging to serogroups A to E were positive for the T6 epitope while 29% of the 96 serotypes (106 strains) belonging to O serogroups F to 67 were negative; 12 serotypes (12 strains) of subspecies IIIb Salmonella were positive for the T6 epitope, but 10 serotypes (11 strains) of subspecies IIIa Salmonella were found to lack this epitope. In T6-positive strains, the epitope was accessible to antibody binding in both the unsubstituted free rough core LPS and in the rough core LPS substituted with a few repeating units of O side chains. The presence or absence of the T6 epitope in Salmonella strains was not affected by culture conditions, the source of the isolate, the age of the culture or the presence of fimbriae antigens.
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Affiliation(s)
- R S Tsang
- Department of Microbiology, University of Hong Kong, Queen Mary Hospital Compound
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