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Structure type: polymer chemical repeating unit
Compound class: O-polysaccharide, O-antigen, LPS
Contained glycoepitopes: IEDB_130648,IEDB_133754,IEDB_136105,IEDB_137473,IEDB_225177,IEDB_885823

• Article ID: 938
  Linnerborg M, Widmalm G, Weintraub A, Albert MJ "Structural elucidation of the O-antigen lipopolysaccharide from two strains of Plesiomonas shigelloides that share a type-specific antigen with Shigella flexneri serotype 6, and the common group 1 antigen with Shigella flexneri spp and Shigella dysenteriae" - European Journal of Biochemistry 231 (1995) 839-844
  

  Sugar and methylation analyses of native polysaccharides together with one-dimensional 1H- and 13C NMR spectroscopy revealed that the two polysaccharides from strains 22074 and 12254 of Plesiomonas shigelloides are identical. The structure of the polysaccharide from strain 22074 was deduced from a uronic acid degradation and by NMR spectroscopy where heteronuclear multiple bond connectivity and two-dimensional nuclear Overhauser effect spectroscopy experiments established the pentasaccharide repeating unit as →4)-α-D-GalpA-(1→3)-α-D-GlcpNAc-(1→3)-α-L-Rhap-(1→2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→.

  Lipopolysaccharide, NMR, antigen, LPS, common, strain, structural, O-antigen, O antigen, group, Shigella flexneri, type, specific, elucidation, Shigella, Shigella dysenteriae, type-specific, Plesiomonas, Plesiomonas shigelloides

  NCBI PubMed ID: 7544287
  Journal NLM ID: 0107600
  Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
  Institutions: Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, Sweden, Karolinska Institute, Department of Immunology, Microbiology, Pathology and Infectious Diseases, Division of Clinical Bacteriology, Huddinge University Hospital, Huddinge, Sweden, International Centre for Diarrhoeal Diseases Research, Bangladesh, Dhaka, Bangladesh
  Methods: methylation, NMR-2D, NMR, sugar analysis
  
   
  
  Shigella flexneri 6
  CSDB ID 3228 (all data & tools)
• Article ID: 2359
  Dmitriev BA, Knirel YA, Sheremet OK, Shashkov AA, Kochetkov NK, Gofman IL "Somatic antigens of Shigella. The structure of the specific polysaccharide of Shigella newcastle (Sh. flexneri type 6) lipopolysaccharide" - European Journal of Biochemistry 98 (1979) 309-316
  
  Journal NLM ID: 0107600
  Publisher: Oxford, UK: Blackwell Science Ltd. on behalf of the Federation of European Biochemical Societies
  Methods: 13C NMR, 1H NMR
  
   
  
  Shigella newcastle, Shigella flexneri 6
  CSDB ID 122486 (all data & tools)
• Article ID: 3506
  Liu B, Knirel YA, Feng L, Perepelov AV, Senchenkova SN, Wang Q, Reeves P, Wang L "Structure and genetics of Shigella O antigens" - FEMS Microbiology Reviews 32(4) (2008) 627-653
  

  This review covers the O antigens of the 46 serotypes of Shigella, but those of most Shigella flexneri are variants of one basic structure, leaving 34 Shigella distinct O antigens to review, together with their gene clusters. Several of the structures and gene clusters are reported for the first time and this is the first such group for which structures and DNA sequences have been determined for all O antigens. Shigella strains are in effect Escherichia coli with a specific mode of pathogenicity, and 18 of the 34 O antigens are also found in traditional E. coli. Three are very similar to E. coli O antigens and 13 are unique to Shigella strains. The O antigen of Shigella sonnei is quite atypical for E. coli and is thought to have transferred from Plesiomonas. The other 12 O antigens unique to Shigella strains have structures that are typical of E. coli, but there are considerably more anomalies in their gene clusters, probably reflecting recent modification of the structures. Having the complete set of structures and genes opens the way for experimental studies on the role of this diversity in pathogenicity.

  structure, O antigen, Shigella, O antigen gene cluster, O antigen diversity

  NCBI PubMed ID: 18422615
  Publication DOI: 10.1111/j.1574-6976.2008.00114.x
  Journal NLM ID: 8902526
  Publisher: Oxford University Press
  Correspondence: wanglei@nankai.edu.cn
  Institutions: TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China, TEDA School of Biological Sciences and Biotechnology, Nankai University, TEDA, Tianjin, China.
  Methods: 13C NMR, 1H NMR, NMR-2D, sugar analysis, ESI-MS, serological methods, genetic methods, biochemical methods
  
   
  
  Shigella flexneri F6, Escherichia coli O147
  CSDB ID 23081 (all data & tools)
• Article ID: 3917
  Passwell JH, Ashkenzi S, Banet-Levi Y, Ramon-Saraf R, Farzam N, Lerner-Geva L, Even-Nir H, Yerushalmi B, Chu C, Shiloach J, Robbins JB, Schneerson R "Age-related efficacy of Shigella O-specific polysaccharide conjugates in 1-4-year-old Israeli children" - Vaccine 28(10) (2010) 2231-2235
  

  BACKGROUND: Despite its high worldwide morbidity and mortality, there is yet no licensed vaccine for shigellosis. We reported the safety and immunogenicity of Shigella O-specific polysaccharide-protein conjugates in adults and young children and efficacy of Shigella sonnei conjugate in young adults. METHODS: A double-blinded, randomized and vaccine-controlled Phase 3 evaluation of S. sonnei and Shigella flexneri 2a O-SP-rEPA conjugates, 25mug, injected IM twice, 6 weeks apart, into healthy 1-4 years old, is reported. The children were followed for 2 years by telephone every other week and stool cultures were obtained for each episode of acute diarrhea (>/=3 loose stools/day or a bloody/mucous stool). Sera were taken randomly from 10% of the participants for IgG anti-LPS and anti-carrier levels. RESULTS: Of the 2799 enrollees, 1433 received S. sonnei and 1366 S. flexneri 2a conjugates; 2699 (96.4%) completed the 2-year follow-up. Local reactions occurred in approximately 5% and approximately 4% had temperatures >/=38.0 degrees C lasting 1-2 days. There were no serious adverse events attributable to the vaccines. Of the 3295 stool cultures obtained, 125 yielded S. sonnei and 21 S. flexneri 2a. Immunogenicity and efficacy were age-related. The overall efficacy of the S. sonnei conjugate was 27.5%; 71.1% (P=0.043) in the 3-4 years old. The numbers for S. flexneri 2a were too few for meaningful analysis. Cross-protection by S. flexneri 2a for non-vaccine S. flexneri types was found, but the numbers were too few for statistical significance. There was an age-related rise of vaccine-specific IgG anti-LPS in both groups, peaking at about 10 weeks and declining thereafter, but remaining >/=4-fold higher than in the controls 2 years after the second dose. CONCLUSIONS: Shigella conjugates are safe and immunogenic in 1-4 years old. The S. sonnei conjugate elicited 71.1% efficacy in the 3-4 years old and can be predicted to be efficacious in individuals older than 3 years of age. These results urge studies with our improved conjugates.

  vaccines, efficacy, shigellosis, Age-related

  NCBI PubMed ID: 20056180
  Journal NLM ID: 8406899
  Publisher: Elsevier
  Correspondence: R. Schneerson
  Institutions: Safra Children's Hospital, Sheba Medical Center, Tel Hashomer 52621, Israel
  Methods: serological methods, statistical analysis
  
   
  
  Shigella flexneri 6
  CSDB ID 25378 (all data & tools)
• Article ID: 4120
  Theillet FX, Simenel C, Guerreiro C, Phalipon A, Mulard LA, Delepierre M "Effects of backbone substitutions on the conformational behaviour of Shigella flexneri O-antigens: implications for vaccine strategy" - Glycobiology 21(1) (2011) 109-121
  

  The O-antigen (O-Ag), the polysaccharide part of the lipopolysaccharide (LPS), is the major target of the serotype-specific protective humoral response elicited upon host infection by Shigella flexneri, the main causal agent of the endemic form of bacillary dysentery. The O-Ag repeat units (RUs) of twelve S. flexneri serotypes share the tetrasaccharide backbone →2)-α-L-Rhap-(1→2)-α-L-Rhap-(1→3)-α-L-Rhap-(1→3)-β-D-GlcpNAc-(1→, with site selective glucosylation(s) and/or O-acetylation defining the serotypes. To investigate the conformational basis of serotype-specificity, we sampled conformational behaviours during 60 ns of molecular dynamic simulations for oligosaccharides representing three RUs of each one of the O-Ags corresponding to serotypes 1a, 1b, 2a, 2b, 3a, 3b, 4a, 4b, 5a, 5b, X and Y, respectively. The calculated trajectories were checked by NMR for 1a, 2a, 3a and 5a O-Ags. The simulations predict that in all O-Ags, but 1a and 1b, serotype-specific substitutions of the backbone do not induce any new backbone conformations compared to the linear type O-Ag Y, although they restrain locally the accessible conformational space. Moreover, the influence of any given substituent on the backbone is independent of the eventual presence of other substituents. Finally, only slight differences of conformational behaviour between terminal and inner RUs were observed. These results suggest that the reported serotype-specificity of the protective immune response is not due to recognition of distinct backbone conformations, but to binding of the serotype-defining substituents in the O-Ag context. The gained knowledge is discussed in terms of impact on the development of a broad-serotype coverage vaccine.

  O-antigen, Shigella flexneri, vaccine, conformational behaviour, polysaccharide substitutions

  NCBI PubMed ID: 21030536
  Journal NLM ID: 9104124
  Publisher: IRL Press at Oxford University Press
  Correspondence: theillet@fmp-berlin.de
  Institutions: Unite de RMN des Biomolecules, CNRS URA 2185, Institut Pasteur, 25-28 rue du Dr Roux, Paris Cedex 15, France
  Methods: conformation analysis, MD simulations
  
   
  
  Shigella flexneri 6
  CSDB ID 26508 (all data & tools)
• Article ID: 4651
  Ewing WH, Lindberg AA "Serology of Shigella" - Book: Methods in Microbiology (1984) Vol. 14, 113-142
  

  This chapter discusses the principles for serology of Shigella. The Shigella organisms are members of the family Enterobacteriaceae and the tribe Escherichieae. The serotytping of shigellae depends upon the determination of O-antigens and O-antigen factors. As shigellae are non-flagellar, H-(flagellar)-antigens are not involved. Fewer antisera are, therefore, required for a complete serotyping of Shigella. The O-antigens heat-stable somatic lipopolysaccharide (LPS) cell wall antigens of known serotypes of Shigella are closely related to those of one or another of the numerous O-antigen groups of Escherichia coli (E. coli). An analysis of lipopolysaccharides from Shigella has unraveled the structure of the O-antigenic polysaccharide chain in the LPS of the bacterial outer membrane. Within the Shigella species, confirmed by their biochemical reactions, a subdivision into serotypes is based on the reactivity of isolated bacteria with a set of antibody preparations. Only the antigenic specificity found in the polysaccharide O-antigenic part of the LPS of the cell envelope is used for typing purposes.

  serology, Salmonella, review

  Publication DOI: 10.1016/S0580-9517(08)70448-3
  Publisher: London, Academic Press
  Editors: Bergan T
  Institutions: Decatur, Georgia, USA and Department of Bacteriology, National Bacteriological Laboratory and Karolinska Institute, Department of Clinical Bacteriology, Huddinge University Hospital, Huddinge, Sweden
  
   
  
  Shigella flexneri 6
  CSDB ID 30182 (all data & tools)
• Article ID: 4936
  Kuttel MM, Stahle J, Widmalm G "CarbBuilder: Software for building molecular models of complex oligo- and polysaccharide structures" - Journal of Computational Chemistry 37(22) (2016) 2098-2105
  

  CarbBuilder is a portable software tool for producing three-dimensional molecular models of carbohydrates from the simple text specification of a primary structure. CarbBuilder can generate a wide variety of carbohydrate structures, ranging from monosaccharides to large, branched polysaccharides. Version 2.0 of the software, described in this article, supports monosaccharides of both mammalian and bacterial origin and a range of substituents for derivatization of individual sugar residues. This improved version has a sophisticated building algorithm to explore the range of possible conformations for a specified carbohydrate molecule. Illustrative examples of models of complex polysaccharides produced by CarbBuilder demonstrate the capabilities of the software. CarbBuilder is freely available under the Artistic License 2.0 from https://people.cs.uct.ac.za/~mkuttel/Downloads.html

  carbohydrate, Shigella flexneri, carbohydrate structure, polysaccharide conformation, 3D model, C.Albicans, CarbBuilder, molecular models

  NCBI PubMed ID: 27317625
  Publication DOI: 10.1002/jcc.24428
  Journal NLM ID: 9878362
  Correspondence: mkuttel@cs.uct.ac.za
  Institutions: Department of Computer Science, University of Cape Town, Cape Town, 7701, South Africa, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, Stockholm, S-106 91, Sweden
  Methods: molecular modeling, CarbBuilder
  
   
  
  Shigella flexneri 6a
  CSDB ID 11765 (all data & tools)
• Article ID: 6304
  Richardson NI, Ravenscroft N, Arato V, Oldrini D, Micoli F, Kuttel MM "Conformational and Immunogenicity Studies of the Shigella flexneri Serogroup 6 O-Antigen: The Effect of O-Acetylation" - Vaccines 9(5) (2021) 432
  

  The pathogenic bacterium Shigella is a leading cause of diarrheal disease and mortality, disproportionately affecting young children in low-income countries. The increasing prevalence of antibiotic resistance in Shigella necessitates an effective vaccine, for which the bacterial lipopolysaccharide O-antigen is the primary target. S. flexneri serotype 6 has been proposed as a multivalent vaccine component to ensure broad protection against Shigella. We have previously explored the conformations of S. flexneri O-antigens from serogroups Y, 2, 3, and 5 that share a common saccharide backbone (serotype Y). Here we consider serogroup 6, which is of particular interest because of an altered backbone repeat unit with non-stoichiometric O-acetylation, the antigenic and immunogenic importance of which have yet to be established. Our simulations show significant conformational changes in serogroup 6 relative to the serotype Y backbone. We further find that O-acetylation has little effect on conformation and hence may not be essential for the antigenicity of serotype 6. This is corroborated by an in vivo study in mice, using Generalized Modules for Membrane Antigens (GMMA) as O-antigen delivery systems, that shows that O-acetylation does not have an impact on the immune response elicited by the S. flexneri serotype 6 O-antigen.

  conformation, O-antigen, Shigella flexneri, O-acetylation, molecular modeling, GMMA

  NCBI PubMed ID: 33925465
  Publication DOI: 10.3390/vaccines9050432
  Journal NLM ID: 101629355
  Publisher: Basel, Switzerland: MDPI AG
  Correspondence: mkuttel@cs.uct.ac.za
  Institutions: Department of Chemistry, University of Cape Town, Rondebosch 7701, South Africa, Department of Computer Science, University of Cape Town, Rondebosch 7701, South Africa, GSK Vaccines Institute for Global Health (GVGH) S.r.l., via Florentina 1, 53100 Siena, Italy
  Methods: PCR, ELISA, MD simulations, statistical analysis, immunological assays, HPLC-SEC, CarbBuilder, GMMA-technology, data analysis, PMF calculations, immunogenicity studies in mice
  
   
  
  Shigella flexneri 6
  CSDB ID 9179 (all data & tools)