1
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Rohokale R, Guo Z. Development in the Concept of Bacterial Polysaccharide Repeating Unit-Based Antibacterial Conjugate Vaccines. ACS Infect Dis 2023; 9:178-212. [PMID: 36706246 PMCID: PMC9930202 DOI: 10.1021/acsinfecdis.2c00559] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The surface of cells is coated with a dense layer of glycans, known as the cell glycocalyx. The complex glycans in the glycocalyx are involved in various biological events, such as bacterial pathogenesis, protection of bacteria from environmental stresses, etc. Polysaccharides on the bacterial cell surface are highly conserved and accessible molecules, and thus they are excellent immunological targets. Consequently, bacterial polysaccharides and their repeating units have been extensively studied as antigens for the development of antibacterial vaccines. This Review surveys the recent developments in the synthetic and immunological investigations of bacterial polysaccharide repeating unit-based conjugate vaccines against several human pathogenic bacteria. The major challenges associated with the development of functional carbohydrate-based antibacterial conjugate vaccines are also considered.
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Affiliation(s)
- Rajendra Rohokale
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States of America
| | - Zhongwu Guo
- Department of Chemistry, University of Florida, Gainesville, Florida 32611, United States of America
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2
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Aroyl and acyl cyanides as orthogonal protecting groups or as building blocks for the synthesis of heterocycles. Mol Divers 2019; 23:1065-1084. [PMID: 30666490 DOI: 10.1007/s11030-019-09915-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Accepted: 01/04/2019] [Indexed: 10/27/2022]
Abstract
α-Cyanoketones represent a synthetically attractive scaffold possessing bifunctional reactivity which enabled synthesis of a diversity of products. This involves reaction of nucleophiles with electrophilic carbonyl carbon performing an efficient and regioselective way to acylation reaction, cycloaddition of activated cyano function with dipolarophiles, metal-catalyzed cross-dehydrogenative coupling carbocyanation across C-C multiple bonds as well as hydrocyanation. This review provides the recent developments in the chemistry of α-cyanoketones which will be beneficial for researchers and scientists in such field.
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3
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Abstract
The varied landscape of the adaptive immune response is determined by the peptides presented by immune cells, derived from viral or microbial pathogens or cancerous cells. The study of immune biomarkers or antigens is not new, and classical methods such as agglutination, enzyme-linked immunosorbent assay, or Western blotting have been used for many years to study the immune response to vaccination or disease. However, in many of these traditional techniques, protein or peptide identification has often been the bottleneck. Recent progress in genomics and mass spectrometry have led to many of the rapid advances in proteomics approaches. Immunoproteomics describes a rapidly growing collection of approaches that have the common goal of identifying and measuring antigenic peptides or proteins. This includes gel-based, array-based, mass spectrometry-based, DNA-based, or in silico approaches. Immunoproteomics is yielding an understanding of disease and disease progression, vaccine candidates, and biomarkers. This review gives an overview of immunoproteomics and closely related technologies that are used to define the full set of protein antigens targeted by the immune system during disease.
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Affiliation(s)
- Kelly M Fulton
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON, Canada
| | - Isabel Baltat
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON, Canada
| | - Susan M Twine
- Human Health Therapeutics Research Centre, National Research Council of Canada, Ottawa, ON, Canada.
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4
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De Ricco R, Ventura CL, Carboni F, Saksena R, Kováč P, Adamo R. Structure-Immunogenicity Relationship of α- and β-Tetrasaccharide Glycoforms from Bacillus anthracis Exosporium and Fragments Thereof. Molecules 2018; 23:molecules23082079. [PMID: 30127242 PMCID: PMC6222408 DOI: 10.3390/molecules23082079] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2018] [Revised: 08/01/2018] [Accepted: 08/17/2018] [Indexed: 11/16/2022] Open
Abstract
The tetrasaccharide (2-O-methyl-4-(3-hydroxy-3-methylbutamido)-4,6-dideoxy-α-d-glucopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→3)-α-l-rhamnopyranosyl-(1→2)-l-rhamnopyranose) from the major exosporium protein (BclA) of Bacillus anthracis has been proposed as a target for development of diagnostics and immune therapy or prophylaxis. While the immunodominant character of the anthrose residue has been previously elucidated, the role of the stereochemical configuration of the downstream rhamnose is unknown. Because the linkage of this residue to the GlcNAc bridging the glycan and the protein is lost during isolation of the tetrasaccharide, its α- and β-glycoforms have been synthesized. Herein, we prepared neoglycoconjugates from a series of fragments of the tetrasaccharide, including the complete α- and β-tetrasaccharide glycoforms, a 2-demethoxylated version of the α-tetrasaccharide, and the α- and β-trirhamnosides and CRM197. By immunization of mice, we showed that the anti α- and β-tetrasaccharide serum equally recognized both glycoforms. In contrast the sera produced following immunization with the α- and β-trirhamnoside fragments exhibited higher recognition for their own antigens than for their anomeric counterparts. The anti α- and β-tetrasaccharide sera recognized Sterne spores in a comparable fashion. ΔBclA spores not expressing the major exosporium protein were also recognized by the same sera, while mutants that produced the carbohydrate antigen with deletion of either rhamnose or anthrose were not. The tetrasaccharide could, therefore, be expressed in proteins other than BlcA. This work proves that α- and β-tetrasaccharide are equally potent immunogens.
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Affiliation(s)
| | - Christy L Ventura
- Department of Microbiology and Immunology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814, USA.
| | | | - Rina Saksena
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA.
| | - Pavol Kováč
- NIDDK, LBC, National Institutes of Health, Bethesda, MD 20892-0815, USA.
| | - Roberto Adamo
- GSK, Research Centre, via Fiorentina 1, 53100 Siena, Italy.
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5
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Jakas A, Perc M, Suć J, Rodriguez MC, Cudic M, Cudic P. Synthesis of anthrose lipidic derivative as mimic of B. anthracis BclA glycoprotein for use in ELISA-like binding assays. J Carbohydr Chem 2016. [DOI: 10.1080/07328303.2016.1139124] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Affiliation(s)
- Andreja Jakas
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Zagreb, Croatia
| | - Milica Perc
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Zagreb, Croatia
| | - Josipa Suć
- Division of Organic Chemistry and Biochemistry, Rudjer Bošković Institute, Zagreb, Croatia
| | - Maria C. Rodriguez
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, USA
| | - Mare Cudic
- Department of Chemistry and Biochemistry, Florida Atlantic University, Boca Raton, FL, USA
| | - Predrag Cudic
- Torrey Pines Institute for Molecular Studies, Port St. Lucie, FL, USA
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6
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Maes E, Krzewinski F, Garenaux E, Lequette Y, Coddeville B, Trivelli X, Ronse A, Faille C, Guerardel Y. Glycosylation of BclA Glycoprotein from Bacillus cereus and Bacillus anthracis Exosporium Is Domain-specific. J Biol Chem 2016; 291:9666-77. [PMID: 26921321 DOI: 10.1074/jbc.m116.718171] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2016] [Indexed: 11/06/2022] Open
Abstract
The spores of the Bacillus cereus group (B. cereus, Bacillus anthracis, and Bacillus thuringiensis) are surrounded by a paracrystalline flexible yet resistant layer called exosporium that plays a major role in spore adhesion and virulence. The major constituent of its hairlike surface, the trimerized glycoprotein BclA, is attached to the basal layer through an N-terminal domain. It is then followed by a repetitive collagen-like neck bearing a globular head (C-terminal domain) that promotes glycoprotein trimerization. The collagen-like region of B. anthracis is known to be densely substituted by unusual O-glycans that may be used for developing species-specific diagnostics of B. anthracis spores and thus targeted therapeutic interventions. In the present study, we have explored the species and domain specificity of BclA glycosylation within the B. cereus group. First, we have established that the collagen-like regions of both B. anthracis and B. cereus are similarly substituted by short O-glycans that bear the species-specific deoxyhexose residues anthrose and the newly observed cereose, respectively. Second we have discovered that the C-terminal globular domains of BclA from both species are substituted by polysaccharide-like O-linked glycans whose structures are also species-specific. The presence of large carbohydrate polymers covering the surface of Bacillus spores may have a profound impact on the way that spores regulate their interactions with biotic and abiotic surfaces and represents potential new diagnostic targets.
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Affiliation(s)
- Emmanuel Maes
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Frederic Krzewinski
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Estelle Garenaux
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | | | - Bernadette Coddeville
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | - Xavier Trivelli
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
| | | | | | - Yann Guerardel
- From the Université de Lille, CNRS, UMR 8576-UGSF-Unité de Glycobiologie Structurale et Fonctionnelle, F-59000 Lille, France and
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7
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Peterson K, Weymouth-Wilson A, Nilsson UJ. Aryl Sulfonates in Inversions at Secondary Carbohydrate Hydroxyl Groups: A New and Improved Route Toward 3-Azido-3-deoxy-β-d-galactopyranosides. J Carbohydr Chem 2015. [DOI: 10.1080/07328303.2015.1105248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
| | - Alex Weymouth-Wilson
- Dextra Laboratories Ltd., Science & Technology Centre, Earley Gate, Whiteknights Road, Reading, RG6 6BZ, UK
| | - Ulf J. Nilsson
- Centre for Analysis and Synthesis, Lund University, SE 22100, Lund, Sweden
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8
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Adamo R. Glycan surface antigens fromBacillus anthracisas vaccine targets: current status and future perspectives. Expert Rev Vaccines 2014; 13:895-907. [DOI: 10.1586/14760584.2014.924404] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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9
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Abstract
The varied landscape of the adaptive immune response is determined by the peptides presented by immune cells, derived from viral or microbial pathogens or cancerous cells. The study of immune biomarkers or antigens is not new and classical methods such as agglutination, enzyme-linked immunosorbent assay, or Western blotting have been used for many years to study the immune response to vaccination or disease. However, in many of these traditional techniques, protein or peptide identification has often been the bottleneck. Recent advances in genomics and proteomics, has led to many of the rapid advances in proteomics approaches. Immunoproteomics describes a rapidly growing collection of approaches that have the common goal of identifying and measuring antigenic peptides or proteins. This includes gel based, array based, mass spectrometry, DNA based, or in silico approaches. Immunoproteomics is yielding an understanding of disease and disease progression, vaccine candidates, and biomarkers. This review gives an overview of immunoproteomics and closely related technologies that are used to define the full set of antigens targeted by the immune system during disease.
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Affiliation(s)
- Kelly M Fulton
- Human Health Therapeutics, National Research Council Canada, Ottawa, ON, Canada
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10
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Milhomme O, Köhler SM, Ropartz D, Lesur D, Pilard S, Djedaïni-Pilard F, Beyer W, Grandjean C. Synthesis and immunochemical evaluation of a non-methylated disaccharide analogue of the anthrax tetrasaccharide. Org Biomol Chem 2012; 10:8524-32. [PMID: 23010801 DOI: 10.1039/c2ob26131f] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Anthrax tetrasaccharide is an oligosaccharide expressed at the outermost surface of the Bacillus anthracis spores, featuring three rhamnoses and a rare sugar called anthrose. This motif has now been identified as a plausible component of future human vaccines against anthrax. We report herein the synthesis of a 2-O-demethylated-β-D-anthropyranosyl-(1→3)-α-L-rhamnopyranose disaccharide analogue of this tetrasaccharide from a cyclic sulfate intermediate. This disaccharide conjugated to BSA induces an anti-native tetrasaccharide IgG antibody response when administered in BALB/c mice. Moreover, induced sera bound to native B. anthracis endospores. These results suggest that the disaccharide analogue, easily amenable for a synthetic scale-up, could be used in a glycoconjugate antigen formulation.
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Affiliation(s)
- Ophélie Milhomme
- Laboratoire des Glucides, FRE CNRS 3517, Institut de Chimie de Picardie, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex, France
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11
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Fyrner T, Svensson SC, Konradsson P. Synthesis of tri-, penta-, and heptasaccharides, functionalized with orthogonally N-protected amino residues at the reducing and non-reducing ends. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.05.118] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
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12
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Milhomme O, Dhénin SG, Djedaïni-Pilard F, Moreau V, Grandjean C. Synthetic studies toward the anthrax tetrasaccharide: alternative synthesis of this antigen. Carbohydr Res 2012; 356:115-31. [DOI: 10.1016/j.carres.2012.01.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/15/2012] [Accepted: 01/17/2012] [Indexed: 10/14/2022]
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13
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Li D, Truong TV, Bills TM, Holt BC, VanDerwerken DN, Williams JR, Acharya A, Robison RA, Tolley HD, Lee ML. GC/MS Method for Positive Detection of Bacillus anthracis Endospores. Anal Chem 2012; 84:1637-44. [DOI: 10.1021/ac202606x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Dan Li
- Department
of Chemistry and
Biochemistry, Brigham Young University,
Provo, Utah 84602, United States
| | - Tai V. Truong
- Department
of Chemistry and
Biochemistry, Brigham Young University,
Provo, Utah 84602, United States
| | - Teri M. Bills
- Department of Microbiology and
Molecular Biology, Brigham Young University, Provo, Utah 84602, United States
| | - Brian C. Holt
- Department of Statistics, Brigham Young University, Provo, Utah 84602, United
States
| | | | - John R. Williams
- Department
of Chemistry and
Biochemistry, Brigham Young University,
Provo, Utah 84602, United States
| | - Abhilasha Acharya
- Department
of Chemistry and
Biochemistry, Brigham Young University,
Provo, Utah 84602, United States
| | - Richard A. Robison
- Department of Microbiology and
Molecular Biology, Brigham Young University, Provo, Utah 84602, United States
| | - H. Dennis Tolley
- Department of Statistics, Brigham Young University, Provo, Utah 84602, United
States
| | - Milton L. Lee
- Department
of Chemistry and
Biochemistry, Brigham Young University,
Provo, Utah 84602, United States
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14
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Development of aptamer beacons for rapid presumptive detection of Bacillus spores. J Fluoresc 2012; 22:915-24. [PMID: 22218972 DOI: 10.1007/s10895-011-1030-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Accepted: 12/19/2011] [Indexed: 10/14/2022]
Abstract
A library of 92 DNA aptamer sequences was developed against Bacillus anthracis (nonpathogenic Sterne strain) spores and anthrose sugar immobilized on magnetic beads. The selected DNA sequences were studied for similarities and potential binding pockets between the B. anthracis spore and anthrose aptamers. Several recurring loop structures were identified and tested for their potential to act as aptamer beacons when labeled with TYE 665 dye on their 5' ends and Iowa Black quencher on their 3' ends. Of these candidate sequences, two beacons designated BAS-6F and BAS-6R emerged which gave strong fluorescence responses at high spore concentrations (greater than 30,000 spores/ml). These aptamer beacons also detect B. cereus and B. thuringiensis spores with greater fluorescence intensity, but do not strongly detect vegetative cells from an array of other bacterial species. BAS-6F and 6R are also not capable of detecting pure anthrose, thereby probably ruling that epitope out as a spore surface target for these particular beacons. While not extremely sensitive, the BAS-6F and 6R aptamer beacons are potentially valuable for rapid presumptive detection of anthrax or Bacillus spores in suspect powders or bioterrorist activity where spore concentrations are anticipated to be high. The sequence similarities of these beacons to other published Bacillus spore aptamers are also discussed.
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15
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Morelli L, Poletti L, Lay L. Carbohydrates and Immunology: Synthetic Oligosaccharide Antigens for Vaccine Formulation. European J Org Chem 2011. [DOI: 10.1002/ejoc.201100296] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Laura Morelli
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
| | - Laura Poletti
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
| | - Luigi Lay
- Dipartimento di Chimica Organica e Industriale, CISI and ISTM‐CNR, Università degli Studi di Milano, Via Venezian 21, 20133 Milano, Italy
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16
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Milhomme O, John C, Djedaïni-Pilard F, Grandjean C. Access to antigens related to anthrose using pivotal cyclic sulfite/sulfate intermediates. J Org Chem 2011; 76:5985-98. [PMID: 21678952 DOI: 10.1021/jo200340q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Anthrose is the upstream terminal unit of the tetrasaccharide side chain from a major glycoprotein of Bacillus anthracis exosporium and is part of important antigenic determinants. A novel entry to anthrose-containing antigens and precursors is described. The synthetic route, starting from D(+)-fucose, makes use of intermediates featuring a cyclic sulfite or sulfate function which serves successively as a protecting and a leaving group.
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Affiliation(s)
- Ophélie Milhomme
- Laboratoire des Glucides, UMR CNRS 6219, Institut de Chimie de Picardie, Université de Picardie Jules Verne, 33 rue Saint Leu, 80039 Amiens Cedex, France
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17
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Concise synthesis of Bacillus anthracis exosporium tetrasaccharide via two-stage activation of allyl glycosyl donor strategy. Tetrahedron Lett 2011. [DOI: 10.1016/j.tetlet.2011.05.089] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
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18
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Identification of an African Bacillus anthracis lineage that lacks expression of the spore surface-associated anthrose-containing oligosaccharide. J Bacteriol 2011; 193:3506-11. [PMID: 21571994 DOI: 10.1128/jb.00078-11] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The surfaces of Bacillus anthracis endospores expose a pentasaccharide containing the monosaccharide anthrose, which has been considered for use as a vaccine or target for specific detection of the spores. In this study B. anthracis strains isolated from cattle carcasses in African countries where anthrax is endemic were tested for their cross-reactivity with monoclonal antibodies (MAbs) specific for anthrose-containing oligosaccharides. Unexpectedly, none of the isolates collected in Chad, Cameroon, and Mali were recognized by the MAbs. Sequencing of the four-gene operon encoding anthrose biosynthetic enzymes revealed the presence of premature stop codons in the aminotransferase and glycosyltransferase genes in all isolates from Chad, Cameroon, and Mali. Both immunological and genetic findings suggest that the West African isolates are unable to produce anthrose. The anthrose-deficient strains from West Africa belong to a particular genetic lineage. Immunization of cattle in Chad with a locally produced vaccine based on anthrose-positive spores of the B. anthracis strain Sterne elicited an anti-carbohydrate IgG response specific for a synthetic anthrose-containing tetrasaccharide as demonstrated by glycan microarray analysis. Competition immunoblots with synthetic pentasaccharide derivatives suggested an immunodominant role of the anthrose-containing carbohydrate in cattle. In West Africa anthrax is highly endemic. Massive vaccination of livestock in this area has taken place over long periods of time using spores of the anthrose-positive vaccine strain Sterne. The spread of anthrose-deficient strains in this region may represent an escape strategy of B. anthracis.
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20
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Pragani R, Seeberger PH. Total synthesis of the Bacteroides fragilis zwitterionic polysaccharide A1 repeating unit. J Am Chem Soc 2010; 133:102-7. [PMID: 21142035 DOI: 10.1021/ja1087375] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Nearly all bacteria capsular polysaccharides are T-cell-independent antigens that do not promote immunoglobulin class switching from IgM to IgG nor memory responses. In contrast, zwitterionic polysaccharides activate T-cell-dependent immune responses by major histocompatability complex class II presentation, a mechanism previously believed to be reserved for peptidic antigens. The best studied zwitterionic polysaccharide, polysaccharide A1 (PS A1) is found on the capsule of the commensal bacteria Bacteroides fragilis . Its potent immunomodulatory properties have been linked to postoperative intra-abdominal abscess formation. Here, we report the synthesis of the PS A1 tetrasaccharide repeating unit (2) as a tool to investigate the biological role of this polysaccharide. A modular synthetic strategy originating from the reducing end of the PS A1 repeating unit was unsuccessful and illustrated the limitations of glycosylation reactions between highly armed glycosylating agents and poor nucleophiles. Thus, a [3 + 1] glycosylation relying on trisaccharide 5 and pyruvalated galactose 6 was used to complete the first total synthesis of the PS A1 repeating unit (2).
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Affiliation(s)
- Rajan Pragani
- Max Planck Institute of Colloids and Interfaces, Department of Biomolecular Systems, Am Mühlenberg 1, 14476 Potsdam, Germany
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21
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22
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Dhénin SGY, Moreau V, Nevers MC, Créminon C, Djedaïni-Pilard F. Sensitive and specific enzyme immunoassays for antigenic trisaccharide from Bacillus anthracis spores. Org Biomol Chem 2009; 7:5184-99. [PMID: 20024115 DOI: 10.1039/b914534f] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A straightforward synthesis of an anthrose-containing trisaccharide derived from Bacillus anthracis was achieved. Antibodies raised against this hapten provide a highly sensitive enzyme immunoassay with a detection limit of 8.5 pmol mL(-1). By investigating the specificity of the antibodies obtained using different mono-, di- and trisaccharide synthetic analogues, we demonstrated that the epitope was mainly made up of the methyl group at C-5, the butamido group at C-4 and the hydroxyl at C-3 of the anthrose unit, the other parts of the trisaccharide appearing little involved in the recognition.
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Affiliation(s)
- Sandrine G Y Dhénin
- Laboratoire des Glucides, UMR-CNRS 6219, Institut de Chimie de Picardie, Université de Picardie Jules Verne, 33 rue St Leu, F-80039, Amiens, France
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