The conformation of core oligosaccharides from <i>Escherichia coli</i> and <i>Salmonella typhimurium</i> lipopolysaccharides as predicted by semi‐empirical calculations

Jansson, Per‐Erik; Wollin, Ralfh; Bruse, Gert W.; Lindberg, Alf A.

doi:10.1002/jmr.300020105

Cited by 12 publications

(8 citation statements)

References 14 publications

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“…Moreover, conformational similarities in the outer core (hexose region) of Salmonella spp. and of E. coli Rl to R4 and K-12 LPS have been predicted by semiempirical calculations (29). These results are in line with our data which suggest that the outer core may contribute to the Ab binding surface.…”

Section: Discussionsupporting

confidence: 92%

A broadly cross-protective monoclonal antibody binding to Escherichia coli and Salmonella lipopolysaccharides

et al. 1993

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During the last decade, episodes of sepsis have increased and Escherichia coli has remained the most frequent clinical isolate. Lipopolysaccharides (LPS; endotoxin) are the major toxic and antigenic components of gram-negative bacteria and qualify as targets for therapeutic interventions. Molecules that neutralize the toxic effects of LPS are actively investigated. In this paper, we describe a murine monoclonal antibody (MAb; WN1 222-5), broadly cross-reactive and cross-protective for smooth (S)-form and rough (R)-form LPS. As shown in enzyme-linked immunosorbent assay and the passive hemolysis assay, WN1 222-5 binds to the five known E. coli core chemotypes, to SalmoneUla core, and to S-form LPS having these core stmctures. In immunoblots, it is shown to react with both the nonsubstituted core LPS and with LPS carrying 0-side chains, indicating the exposure of the epitope in both S-form and R-form LPS. This MAb of the immunoglobulin G2a class is not lipid A reactive but binds to E. coli J5, an RcP+ mutant which carries an inner core structure common to many members of the family Enterobacteriaceae. Phosphate groups present in the inner core contribute to the epitope but are not essential for the binding of WN1 222-5 to complete core LPS. Cross-reactivity for clinical bacterial isolates is broad. WN1 222-5 binds to all E. coli clinical isolates tested so far (79 blood isolates, 80 urinary isolates, and 21 fecal isolates) and to some Citrobacter, Enterobacter, and KiebsieUla isolates. This pattern of reactivity indicates that its binding epitope is widespread among members of the Enterobacteriaceae. WN1 222-5 exhibits biologically relevant activities. In vitro, it inhibits the Limulu amoebocyte lysate assay activity of S-form and R-form LPS in a dose-dependent manner and it neutralizes the LPS-induced release of clinically relevant monokines (interleukin 6 and tumor necrosis factor). In vivo, WN1 222-5 blocks endotoxin-induced pyrogenicity in rabbits and lethality in galactosamine-sensitized mice. The discovery of WN1 222-5 settles the long-lasting controversy over the existence of anti-core LPS MAbs with both cross-reactive and cross-protective activity, opening new possibilities for the immunotherapy of sepsis caused by gram-negative bacteria. * Corresponding author. phipathic, microheterogeneous macromolecules which consist of three regions: the 0-specific polysaccharide chain, the core oligosaccharide, and lipid A. These regions are genetically, biochemically, and antigenically distinct, but the core region and lipid A retain common structural features (47). In members of the family Enterobacteriaceae, the 0-specific side chains are composed of repeating oligosaccharide units and are highly variable in structure and composition, giving rise to the high number of serotypes known. The core comprises an outer and inner region, the latter being phylogenetically more conserved. Five different chemotypes (Rl, R2, R3, R4, and K-12) are known among E. coli strains, but only one core structure accounts for all Salmonel...

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Section: Discussionsupporting

confidence: 92%

A broadly cross-protective monoclonal antibody binding to Escherichia coli and Salmonella lipopolysaccharides

et al. 1993

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“…A unique binding site for the R2-specific antibody is not obvious from the structural formulas. From the calculated three-dimensional structure of the different core types [24], however, it appears that the branch-terminating a 1-6 galactose present in R2, Salmonel/a core, and K 12 may be in a different orientation in R2 and may therefore be the R2-specific epitope. It is of note that while most of the core-specific MAbs reacted in immunoblot only with unsubstituted core, the R2-specific MAb also reacted with a-substituted core, giving a ladder pattern in immunoblots.…”

Section: Discussionmentioning

confidence: 99%

Frequencies of Lipopolysaccharide Core Types among Clinical Isolates of Escherichia coli Defined with Monoclonal Antibodies

Gibb¹,

Barclay²,

Poxton³

et al. 1992

Journal of Infectious Diseases

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Mouse monoclonal antibodies (MAbs) specific for the lipopolysaccharide (LPS) core types R1, R2, and R3 of Escherichia coliand a cross-reactive MAb that binds to the LPS core of almost all E. coli were used in ELISA to determine the frequency of cores resembling R1, R2, and R3 in strains of E. coli isolated from clinical samples (blood and urine specimens) and from the feces of asymptomatic individuals. Of the 180 wild-type isolates, 123 were assigned to R1 core type, 14 to R2, and 18 to R3. Twenty-five wild-type E. coliisolates could not be assigned to a particular core type and may have either an R4 or K12 core or a previously unrecognized core type. R1 core type was associated with 0 types 1,4,6,8, and 18 and with K1 or K5 capsules. R3 was associated with 015. 075 isolates could be of either R1 or R2 core type.The lipopolysaccharide (LPS) core region of Escherichia coli has a conserved overall structure, with an inner 2-keto-3-deoxy-octonate-heptose region and an outer hexose region. Most of the variation that does occur is in the outer part of the core, furthest from lipid A. In wild-type smooth E. coli. the core region can occur in at least four different forms, known as R 1, R2, R3, and R4 [1][2][3]. The naturally rough strain Kl2 has a different core region [4].The 0 antigen of smooth LPS may mask some of the epitopes and phage attachment sites in the core region. The chemical, serologic, and phage typing methods that have been used to define the different core types of E. coli are therefore not directly applicable to wild-type smooth strains. The frequency with which these different core types occur in wild-type E. coli is therefore not known.Little is known about the association between core types and 0 serotypes ofE. coli. except that the original R 1 and R2 rough mutants were both derived from 08 strains [I] and that the original R3 mutant was derived from an 0 III strain [2]. There is no published evidence on the relationship of LPS core types to capsular types or to virulence. Information about the distribution of 0 and K antigens has proved to be useful, for example in identifying and understanding enteropathogenic strains [5] and in suggesting novel therapeutic approaches to bacteremia [6]. Information about core types might be equally interesting.We therefore set out to produce a panel ofmouse monoclo- Materials and MethodsBacteria and bacteriophages. E. coli RI (F470), R2 (F576), R3 (F653), R4 (2513) and KI2 (2131) and rough-specific phages FO, BrIO, C21, 6SR, and T4 were obtained from G. Schmidt (Forschunginstitut, Borstel, Germany). E. coli 0 I, 02, 04, 06, 012, 015, 018, and 075 were obtained from A. S. Cross (Walter Reed Army Institute, Washington, DC). Phages specific for E. coli capsular types KI (KIGS) and K5 (K5DG) were obtained from A. P. Roberts (Charing Cross and Westminster Medical School, London). Blood culture and urine isolates were obtained from the Clinical Bacteriology Laboratory, Department of Medical Microbiology, Edinburgh University, from routine clinical specimens. ...

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“…Synthesized mono‐, di‐ or trisaccharide could be used for this purpose. Alternatively, previous studies have demonstrated that the sugar composition has an influence on the conformation of the core OS (Jansson et al ., 1989; Bruse et al ., 1991). Thus, the loss of the GalNAc‐Gal II‐Gal I region might lead to a conformation that is less able to bind the toxins.…”

Section: Discussionmentioning

confidence: 99%

Mutation in the LPS outer core biosynthesis gene, galU, affects LPS interaction with the RTX toxins ApxI and ApxII and cytolytic activity of Actinobacillus pleuropneumoniae serotype 1

Ramjeet

Cox

Hancock

et al. 2008

Molecular Microbiology

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SummaryLipopolysaccharides (LPS) and Apx toxins are major virulence factors of Actinobacillus pleuropneumoniae, a pathogen of the respiratory tract of pigs. Here, we evaluated the effect of LPS core truncation in haemolytic and cytotoxic activities of this microorganism. We previously generated a highly attenuated galU mutant of A. pleuropneumoniae serotype 1 that has an LPS molecule lacking the GalNAc-Gal II-Gal I outer core residues. Our results demonstrate that this mutant exhibits wild-type haemolytic activity but is significantly less cytotoxic to porcine alveolar macrophages. However, no differences were found in gene expression and secretion of the haemolytic and cytotoxic toxins ApxI and ApxII, both secreted by A. pleuropneumoniae serotype 1. This suggests that the outer core truncation mediated by the galU mutation affects the toxins in their cytotoxic activities. Using both ELISA and surface plasmon resonance binding assays, we demonstrate a novel interaction between LPS and the ApxI and ApxII toxins via the core oligosaccharide. Our results indicate that the GalNAc-Gal II-Gal I trisaccharide of the outer core is fundamental to mediating LPS/Apx interactions. The present study suggests that a lack of binding between LPS and ApxI/II affects the cytotoxicity and virulence of A. pleuropneumoniae.

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The conformation of core oligosaccharides from Escherichia coli and Salmonella typhimurium lipopolysaccharides as predicted by semi‐empirical calculations

Cited by 12 publications

References 14 publications

A broadly cross-protective monoclonal antibody binding to Escherichia coli and Salmonella lipopolysaccharides

A broadly cross-protective monoclonal antibody binding to Escherichia coli and Salmonella lipopolysaccharides

Frequencies of Lipopolysaccharide Core Types among Clinical Isolates of Escherichia coli Defined with Monoclonal Antibodies

Mutation in the LPS outer core biosynthesis gene, galU, affects LPS interaction with the RTX toxins ApxI and ApxII and cytolytic activity of Actinobacillus pleuropneumoniae serotype 1

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