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Gitsels A, Van Lent S, Sanders N, Vanrompay D. Chlamydia: what is on the outside does matter. Crit Rev Microbiol 2020; 46:100-119. [PMID: 32093536 DOI: 10.1080/1040841x.2020.1730300] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
This review summarises major highlights on the structural biology of the chlamydial envelope. Chlamydiae are obligate intracellular bacteria, characterised by a unique biphasic developmental cycle. Depending on the stage of their lifecycle, they appear in the form of elementary or reticulate bodies. Since these particles have distinctive functions, it is not surprising that their envelope differs in lipid as well as in protein content. Vice versa, by identifying surface proteins, specific characteristics of the particles such as rigidity or immunogenicity may be deduced. Detailed information on the bacterial membranes will increase our understanding on the host-pathogen interactions chlamydiae employ to survive and grow and might lead to new strategies to battle chlamydial infections.
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Affiliation(s)
- Arlieke Gitsels
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Sarah Van Lent
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
| | - Niek Sanders
- Laboratory of Gene Therapy, Department of Nutrition, Genetics and Ethology, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Daisy Vanrompay
- Laboratory of Immunology and Animal Biotechnology, Department of Animal Sciences and Aquatic Ecology, Faculty of Bioscience Engineering, Ghent University, Ghent, Belgium
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2
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Haji-Ghassemi O, Müller-Loennies S, Brooks CL, MacKenzie CR, Caveney N, Van Petegem F, Brade L, Kosma P, Brade H, Evans SV. Subtle Changes in the Combining Site of the Chlamydiaceae-Specific mAb S25-23 Increase the Antibody-Carbohydrate Binding Affinity by an Order of Magnitude. Biochemistry 2019; 58:714-726. [PMID: 30571096 DOI: 10.1021/acs.biochem.8b00318] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Murine antibodies S25-23, S25-26, and S25-5 derive from a common germ-line origin, and all bind the Chlamydiaceae family-specific epitope αKdo(2→8)αKdo(2→4)αKdo (where Kdo is 3-deoxy-α-d- manno-oct-2-ulosonic acid) with high affinity and specificity. These antibodies recognize the entire trisaccharide antigen in a linkage-dependent manner via a groove composed largely of germ-line residues. Despite sharing identical heavy and light chain genes, S25-23 binds the family-specific epitope with nanomolar affinity, which is an order of magnitude higher than that of S25-26, while S25-5 displays an affinity between those of S25-23 and S25-26. We determined the high-resolution crystal structures of S25-23 and S25-5 antigen binding fragments in complex with a pentasaccharide derived from the LPS of Chlamydia and measured the affinity of S25-5 for chlamydial LPS antigens using isothermal titration microcalorimetry. The 1.75 Å resolution structure of S25-23 shows how subtle conservative mutations Arg(L)-27E to lysine and Ser(H)-56 to threonine lead to an order of magnitude increase in affinity. Importantly, comparison between previous S25-26 structures and the 1.99 and 2.05 Å resolution liganded and unliganded structures of S25-5, respectively, shows how a Ser(L)-27E mutation results in an intermediate affinity due to the reduced enthalpic penalty associated with complex formation that would otherwise be required for arginine in this position. This strategy allows for subtle adjustments in the combining site via affinity maturation that have dramatic consequences for the affinity of an antibody for its antigen.
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Affiliation(s)
- Omid Haji-Ghassemi
- Department of Biochemistry and Microbiology , University of Victoria , P.O. Box 3055 STN CSC, Victoria , British Columbia , Canada V8P 3P6
| | - Sven Müller-Loennies
- Research Center Borstel , Leibniz Lung Center , Parkallee 22 , Borstel D-23845 , Germany
| | - Cory L Brooks
- Department of Chemistry , Fresno State University , 2555 East San Ramon Avenue, MS SB70 , Fresno , California 93740 , United States
| | - C Roger MacKenzie
- Human Health Therapeutics Portfolio , National Research Council Canada , 100 Sussex Drive , Ottawa , Ontario , Canada K1A 0R6
| | - Nathanael Caveney
- Department of Biochemistry and Microbiology , University of Victoria , P.O. Box 3055 STN CSC, Victoria , British Columbia , Canada V8P 3P6
| | - Filip Van Petegem
- Department of Chemistry , University of Natural Resources and Life Sciences , A-1190 Vienna , Austria
| | - Lore Brade
- Research Center Borstel , Leibniz Lung Center , Parkallee 22 , Borstel D-23845 , Germany
| | - Paul Kosma
- Department of Chemistry , University of Natural Resources and Life Sciences , A-1190 Vienna , Austria
| | - Helmut Brade
- Research Center Borstel , Leibniz Lung Center , Parkallee 22 , Borstel D-23845 , Germany
| | - Stephen V Evans
- Department of Biochemistry and Microbiology , University of Victoria , P.O. Box 3055 STN CSC, Victoria , British Columbia , Canada V8P 3P6
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Finethy R, Coers J. Sensing the enemy, containing the threat: cell-autonomous immunity to Chlamydia trachomatis. FEMS Microbiol Rev 2018; 40:875-893. [PMID: 28201690 DOI: 10.1093/femsre/fuw027] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 03/31/2016] [Accepted: 07/01/2016] [Indexed: 01/01/2023] Open
Abstract
The bacterium Chlamydia trachomatis is the etiological agent of the most common sexually transmitted infection in North America and Europe. Medical complications resulting from genital C. trachomatis infections arise predominantly in women where the initial infections often remain asymptomatic and thus unrecognized. Untreated asymptomatic infections in women can ascend into the upper genital tract and establish persistence, ultimately resulting in extensive scarring of the reproductive organs, pelvic inflammatory disease, infertility and ectopic pregnancies. Previously resolved C. trachomatis infections fail to provide protective immune memory, and no effective vaccine against C. trachomatis is currently available. Critical determinants of the pathogenesis and immunogenicity of genital C. trachomatis infections are cell-autonomous immune responses. Cell-autonomous immunity describes the ability of an individual host cell to launch intrinsic immune circuits that execute the detection, containment and elimination of cell-invading pathogens. As an obligate intracellular pathogen C. trachomatis is constantly under attack by cell-intrinsic host defenses. Accordingly, C. trachomatis evolved to subvert and co-opt cell-autonomous immune pathways. This review will provide a critical summary of our current understanding of cell-autonomous immunity to C. trachomatis and its role in shaping host resistance, inflammation and adaptive immunity to genital C. trachomatis infections.
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Affiliation(s)
- Ryan Finethy
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA
| | - Jörn Coers
- Department of Molecular Genetics and Microbiology, Duke University Medical Center, Durham, NC, USA.,Department of Immunology, Duke University Medical Center, Durham, NC, USA
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Müller-Loennies S, Grimmecke D, Brade L, Lindner B, Kosma P, Brade H. A novel strategy for the synthesis of neoglycoconjugates from deacylated deep rough lipopolysaccharides. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/09680519020080040601] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
We report a novel strategy for the preparation of neoglycoconjugates of oligosaccharides which are obtained after complete deacylation of bacterial deep rough lipopolysaccharides (LPS) isolated from recombinant Escherichia coli bacteria synthesizing a Kdo di-[α-Kdo-(2→4)-α-Kdo-(2→] and a Kdo trisaccharide [α-Kdo-(2→8)-α-Kdo-(2→4)-α-Kdo-(2→] of Re-type and chlamydial LPS, respectively. Unlike acylated LPS, such oligosaccharides can be obtained in pure form and thus lead to well-defined neoglycoconjugates. Cleavage of the 1-phosphate of the lipid A moiety by alkaline phosphatase treatment leads to a free reducing glucosamine which can be further reacted with allylamine. After reductive amination, spacer elongation of the allyl group with cysteamine and activation with thiophosgene, the ligands were reacted with BSA. We have compared the immunological reactivity of such defined neoglycoconjugates obtained from natural sources with those obtained by chemical synthesis and report that such neoglycoconjugates are immunogenic and well suited as antigens for the study of epitope specificities of monoclonal antibodies. In addition, we have compared these conjugates with those in which ligands were coupled by glutardialdehyde to BSA. Our approach proved to be superior since the latter led upon immunization of mice to a relatively high percentage of antibodies that reacted with glutardialdehyde derivatized BSA without the carbohydrate ligand. This was not the case for cysteamine-spacered ligands coupled via their isothiocyanate-derivatives.
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Affiliation(s)
- Sven Müller-Loennies
- Division of Biochemical and Medical Microbiology, Center for Medicine and Biosciences, Research Center Borstel, Germany
| | - Dieter Grimmecke
- Division of Biochemical and Medical Microbiology, Center for Medicine and Biosciences, Research Center Borstel, Germany
| | - Lore Brade
- Division of Biochemical and Medical Microbiology, Center for Medicine and Biosciences, Research Center Borstel, Germany,
| | - Buko Lindner
- Division of Biophysics, Center for Medicine and Biosciences, Research Center Borstel, Borstel, Germany
| | - Paul Kosma
- Institute of Chemistry, University of Agricultural Sciences, Vienna, Austria
| | - Helmut Brade
- Division of Biochemical and Medical Microbiology, Center for Medicine and Biosciences, Research Center Borstel, Germany
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Müller R, Brade H, Kosma P. Synthesis of deoxy analogues of (2→8)-linked 3-deoxy-α-D-manno-oct-2-ulopyranosylonic acid (Kdo) disaccharides for binding studies with Chlamydia specific monoclonal antibodies. ACTA ACUST UNITED AC 2016. [DOI: 10.1177/096805199700400506] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Deoxy analogues of the Chlamydia-specific, α-(2→8)-linked Kdo disaccharide epitope modified at the pyranose ring of the terminal Kdo unit have been prepared. Utilizing the 3,5-dideoxy-D-arabino-oct-2-ulosonate bromide donor [1] and the acceptor [2] under Helferich conditions, the 5-deoxy-α-Kdo-(2→8)-α-Kdo disaccharide [3] was obtained as the minor product together with unsaturated, α-(2→8)-glycosidically and (4→8)-ether-linked derivatives [5] and [7] as the major components. Deprotection afforded the disaccharide allyl glycosides [4], [6], and [8]. Further transformation of protected intermediates by hydrogenation followed by deblocking gave the propyl glycosides [12], [14] and [17]. The compounds may be used for binding studies with Chlamydia-specific and cross-reactive, Kdospecific monoclonal antibodies.
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Affiliation(s)
- R. Müller
- Institute of Chemistry, University of Agricultural Sciences, Muthgasse 18, A-1190 Vienna, Austria
| | - H. Brade
- Research Center Borstel, Parkallee 22, D-23845 Borstel, Germany
| | - P. Kosma
- Institute of Chemistry, University of Agricultural Sciences, Muthgasse 18, A-1190 Vienna, Austria
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Haji-Ghassemi O, Blackler RJ, Martin Young N, Evans SV. Antibody recognition of carbohydrate epitopes†. Glycobiology 2015; 25:920-52. [PMID: 26033938 DOI: 10.1093/glycob/cwv037] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Accepted: 05/24/2015] [Indexed: 12/14/2022] Open
Abstract
Carbohydrate antigens are valuable as components of vaccines for bacterial infectious agents and human immunodeficiency virus (HIV), and for generating immunotherapeutics against cancer. The crystal structures of anti-carbohydrate antibodies in complex with antigen reveal the key features of antigen recognition and provide information that can guide the design of vaccines, particularly synthetic ones. This review summarizes structural features of anti-carbohydrate antibodies to over 20 antigens, based on six categories of glyco-antigen: (i) the glycan shield of HIV glycoproteins; (ii) tumor epitopes; (iii) glycolipids and blood group A antigen; (iv) internal epitopes of bacterial lipopolysaccharides; (v) terminal epitopes on polysaccharides and oligosaccharides, including a group of antibodies to Kdo-containing Chlamydia epitopes; and (vi) linear homopolysaccharides.
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Affiliation(s)
- Omid Haji-Ghassemi
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
| | - Ryan J Blackler
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
| | - N Martin Young
- Human Health Therapeutics, National Research Council of Canada, 100 Sussex Drive, Ottawa, ON, Canada K1A 0R6
| | - Stephen V Evans
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, Canada V8P 3P6
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Haji-Ghassemi O, Müller-Loennies S, Saldova R, Muniyappa M, Brade L, Rudd PM, Harvey DJ, Kosma P, Brade H, Evans SV. Groove-type recognition of chlamydiaceae-specific lipopolysaccharide antigen by a family of antibodies possessing an unusual variable heavy chain N-linked glycan. J Biol Chem 2014; 289:16644-61. [PMID: 24682362 DOI: 10.1074/jbc.m113.528224] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The structure of the antigen binding fragment of mAb S25-26, determined to 1.95 Å resolution in complex with the Chlamydiaceae family-specific trisaccharide antigen Kdo(2→8)Kdo(2→4)Kdo (Kdo = 3-deoxy-α-d-manno-oct-2-ulopyranosonic acid), displays a germ-line-coded paratope that differs significantly from previously characterized Chlamydiaceae-specific mAbs despite being raised against the identical immunogen. Unlike the terminal Kdo recognition pocket that promotes cross-reactivity in S25-2-type antibodies, S25-26 and the closely related S25-23 utilize a groove composed of germ-line residues to recognize the entire trisaccharide antigen and so confer strict specificity. Interest in S25-23 was sparked by its rare high μm affinity and strict specificity for the family-specific trisaccharide antigen; however, only the related antibody S25-26 proved amenable to crystallization. The structures of three unliganded forms of S25-26 have a labile complementary-determining region H3 adjacent to significant glycosylation of the variable heavy chain on asparagine 85 in Framework Region 3. Analysis of the glycan reveals a heterogeneous mixture with a common root structure that contains an unusually high number of terminal αGal-Gal moieties. One of the few reported structures of glycosylated mAbs containing these epitopes is the therapeutic antibody Cetuximab; however, unlike Cetuximab, one of the unliganded structures in S25-26 shows significant order in the glycan with appropriate electron density for nine residues. The elucidation of the three-dimensional structure of an αGal-containing N-linked glycan on a mAb variable heavy chain has potential clinical interest, as it has been implicated in allergic response in patients receiving therapeutic antibodies.
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Affiliation(s)
- Omid Haji-Ghassemi
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P 3P6, Canada
| | - Sven Müller-Loennies
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany,
| | - Radka Saldova
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - Mohankumar Muniyappa
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - Lore Brade
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany
| | - Pauline M Rudd
- GlycoScience Group, the National Institute for Bioprocessing Research and Training (NIBRT), Mount Merrion, Blackrock, Dublin 4, Ireland
| | - David J Harvey
- Oxford Glycobiology Institute, Department of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, United Kingdom
| | - Paul Kosma
- University of Natural Resources and Life Sciences, Vienna, Austria, and
| | - Helmut Brade
- Research Center Borstel, Leibniz-Center for Medicine and Biosciences, Parkallee 22, Borstel D-23845, Germany
| | - Stephen V Evans
- From the Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8P 3P6, Canada,
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8
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Cellular distribution of lipid A and LPS R595 after in vitro application to isolated human monocytes by freeze-fracture replica immunogold-labelling. Innate Immun 2013; 19:588-95. [DOI: 10.1177/1753425912473851] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We have performed freeze-fracture replica immunogold labelling of endotoxin preparations (lipid A and deep rough mutant LPS Re from Salmonella enterica sv. Minnesota), i.e. adding the endotoxins to human monocytes, labelling with monoclonal Abs recognizing either lipid A or LPS Re (A6 and A20 respectively), and fixing with immunogold secondary Ab. We have found that the endotoxins intercalated into the cell membranes with subsequent internalization by the cells. Surprisingly, membrane uptake took place only in the inner, plasmic leaflet of the plasma membrane, but there was no uptake of the outer leaflet for both compounds. Remarkable labelling could be also found for the two membranes of the nuclear envelope—in the case of lipid A only at the plasmic leaflet, but in the case of LPS Re on both leaflets. Isothermal calorimetric titration of the AB A20 with LPS and phospholipids showed that the Ab may bind not only to LPS but also to negatively charged phosphatidylserine. These results are discussed in the frame of the published concepts of cell activation induced by the endotoxins, i.e. how they are able to cause a conformational change of signalling proteins, such as the TLR4/MD2 complex.
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Lipooligosaccharide is required for the generation of infectious elementary bodies in Chlamydia trachomatis. Proc Natl Acad Sci U S A 2011; 108:10284-9. [PMID: 21628561 DOI: 10.1073/pnas.1107478108] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Lipopolysaccharides (LPS) and lipooligosaccharides (LOS) are the main lipid components of bacterial outer membranes and are essential for cell viability in most Gram-negative bacteria. Here we show that small molecule inhibitors of LpxC [UDP-3-O-(R-3-hydroxymyristoyl)-GlcNAc deacetylase], the enzyme that catalyzes the first committed step in the biosynthesis of lipid A, block the synthesis of LOS in the obligate intracellular bacterial pathogen Chlamydia trachomatis. In the absence of LOS, Chlamydia remains viable and establishes a pathogenic vacuole ("inclusion") that supports robust bacterial replication. However, bacteria grown under these conditions were no longer infectious. In the presence of LpxC inhibitors, replicative reticulate bodies accumulated in enlarged inclusions but failed to express selected late-stage proteins and transition to elementary bodies, a Chlamydia developmental form that is required for invasion of mammalian cells. These findings suggest the presence of an outer membrane quality control system that regulates Chlamydia developmental transition to infectious elementary bodies and highlights the potential application of LpxC inhibitors as unique class of antichlamydial agents.
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Sixta G, Wimmer K, Hofinger A, Brade H, Kosma P. Synthesis and antigenic properties of C-7-modified Kdo mono- and disaccharide ligands and Kdo disaccharide interresidue lactones. Carbohydr Res 2009; 344:1660-9. [DOI: 10.1016/j.carres.2009.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2009] [Accepted: 06/12/2009] [Indexed: 10/20/2022]
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Sixta G, Hofinger A, Kosma P. Synthesis of spacer-containing chlamydial disaccharides as analogues of the alpha-Kdop-(2-->8)-alpha-Kdop-(2-->4)-alpha-Kdop trisaccharide epitope. Carbohydr Res 2006; 342:576-85. [PMID: 17007824 DOI: 10.1016/j.carres.2006.08.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Accepted: 08/01/2006] [Indexed: 10/24/2022]
Abstract
On the basis of high-resolution crystal structures of the antigen binding fragment of the chlamydia-specific monoclonal antibody S25-2 in complex with the trisaccharide alpha-Kdop-(2-->8)-alpha-Kdop-(2-->4)-alpha-Kdop and part structures thereof, seven modified alpha-Kdop-(2-->8)-alpha-Kdop disaccharide derivatives were synthesized starting from the protected disaccharide allyl ketoside 1. Hydroboration and subsequent oxidation as well as ozonolysis, respectively, followed by Wittig-reaction for chain elongation were used to install a terminal carboxylic group on spacer entities of various chain lengths. Furthermore, addition of methyl 2-thioacetate to the allyl group furnished the corresponding thioether derivative. Standard deprotection gave the target disaccharides as simplified trisaccharide analogues, which will be used to probe the contribution of the proximal carboxylic group in the binding of chlamydia-specific di- and trisaccharide-reactive monoclonal antibodies.
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Affiliation(s)
- Georg Sixta
- Department of Chemistry, University of Natural Resources and Applied Life Sciences, Muthgasse 18, A-1190 Vienna, Austria
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12
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Quevedo Diaz MA, Melnicáková J, Kazár J, Hoch J, Senfleben S, Lukácová M. Detergent extract from chlamydial elementary bodies used as antigen for enzyme-linked immunosorbent assay. Diagn Microbiol Infect Dis 2002; 42:237-42. [PMID: 12007440 DOI: 10.1016/s0732-8893(02)00362-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Soluble antigen (SA) from chlamydial elementary bodies (EBs) was extracted with N-lauroylsarcosine. The extracted SA composed of lipopolysaccharide (LPS) and proteins was compared with EBs using an enzyme-linked immunosorbent assay (ELISA). Patient sera from natural chlamydial infections exhibited ELISA mean absorbance (A(492) and A(405/650)) values 2-5 times higher with SA than with EBs, resulting in a better discrimination between positive and negative human sera.
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Affiliation(s)
- M A Quevedo Diaz
- Institute of Virology, Slovak Academy of Sciences, Dúbravská 9, 84245 Bratislava, Slovak Republic
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13
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Kosma P, Reiter A, Hofinger A, Brade L, Brade H. Synthesis of neoglycoproteins containing Kdo epitopes specific for Chlamydophila psittaci lipopolysaccharide. JOURNAL OF ENDOTOXIN RESEARCH 2001; 6:57-69. [PMID: 11061033 DOI: 10.1177/09680519000060010801] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The oligosaccharides alpha-Kdop-(2-->8)-alpha-Kdop-(2-->6)-beta-D- GlcpNAc-(1-->OAll) 4, alpha-Kdop-(2-->4)-alpha- Kdop-(2-->4)-alpha-Kdop-(2-->6)-beta-D-GlcpNAc-(1-->OAll+ ++) 10, and the branched Kdo tetrasaccharide alpha- Kdop-(2-->4)-[alpha-Kdop-(2-->8)]-alpha-Kdop-(2-->4)-a lpha-Kdop-(2-->OAll) 21 have been prepared using en bloc transfer of Kdo oligosaccharide bromide donors to protected mono- or disaccharide acceptors. Radical addition of cysteamine to the anomeric allyl glycosides afforded good yields of the corresponding 3-(2-aminoethylthio)propyl glycosides 5, 11 and 22. The spacer ligands were activated with thiophosgene and reacted with bovine serum albumin to give the neoglycoconjugates 6, 12 and 23 which were used to prepare solid-phase antigens in enzyme immuno-assays for the characterization of monoclonal antibodies against chlamydial LPS. The data showed that the (2-->8)-linked Kdo disaccharide and the (2-->8)-(2-->4)-linked Kdo trisaccharide portion of the neoglycoconjugate 23 were not available for binding of antibodies which recognize these structures as di- and trisaccharide, respectively.
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Affiliation(s)
- P Kosma
- Department of Chemistry, University of Agricultural Sciences, Vienna, Austria.
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14
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Pozsgay V. Oligosaccharide-protein conjugates as vaccine candidates against bacteria. Adv Carbohydr Chem Biochem 2001; 56:153-99. [PMID: 11039111 DOI: 10.1016/s0065-2318(01)56004-7] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- V Pozsgay
- National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892-2720, USA
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15
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Peterson EM, de la Maza LM, Brade L, Brade H. Characterization of a neutralizing monoclonal antibody directed at the lipopolysaccharide of Chlamydia pneumoniae. Infect Immun 1998; 66:3848-55. [PMID: 9673271 PMCID: PMC108433 DOI: 10.1128/iai.66.8.3848-3855.1998] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Identification of protective epitopes is one of the first steps in the development of a subunit vaccine. One approach to accomplishing this is to identify structures or epitopes by using monoclonal antibodies (MAb) that can attenuate infectivity in vitro and in vivo. To date attempts to use this approach with Chlamydia pneumoniae have failed. This report is the first description of a MAb directed to the lipopolysaccharide (LPS) of Chlamydia that neutralizes both in vitro and in vivo the infectivity of C. pneumoniae. MAb CP-33, an immunoglobulin G2b (IgG2b), was identified from a fusion using splenocytes from mice immunized with C. pneumoniae TW-183. By Western blot analysis, MAb CP-33 exhibited genus-specific reactivity in that it recognized the LPSs of C. pneumoniae, Chlamydia trachomatis, and Chlamydia psittaci. MAb CP-33 did not react with 15 genera of gram-negative and gram-positive bacteria and Candida albicans. By using isolated LPS of Re mutants of Escherichia coli, Salmonella enterica serovar Minnesota, and recombinants expressing the 3-deoxy-D-manno-oct-2-ulosonic acid (Kdo) transferase gene kdtA of C. trachomatis, MAb CP-33 was shown to require for binding the presence of the genus-specific trisaccharide epitope alphaKdo(2-->8)alphaKdo(2-->4)alphaKdo. By employing synthetic oligosaccharides and neoglycoconjugates in an enzyme immunoassay (EIA) and EIA inhibition, it was further shown that MAb CP-33 differed from the extensively investigated prototype chlamydial LPS MAb S25-23. Most likely, MAb CP-33 recognizes a conformational epitope in which the alphaKdo(2-->8)alphaKdo(2-->4)alphaKdo trisaccharide is an essential structural component. When tested in an in vitro neutralization assay, MAb CP-33 gave a 50% neutralization titer of 8 ng/ml against C. pneumoniae TW-183. However, this MAb did not neutralize other C. pneumoniae strains, C. trachomatis, or C. psittaci. C. pneumoniae TW-183 was treated with either MAb CP-33 or a control IgG and then used to inoculate mice by the respiratory route. Five days after inoculation, there was a difference between the mice inoculated with the control IgG-treated inoculum and those inoculated with the MAb CP-33-treated organisms as to the number of mice infected as well as the number of inclusion-forming units recovered from lung cultures (P < 0.05). In summary, a Chlamydia-specific LPS MAb was able to neutralize in vitro the infectivity of C. pneumoniae TW-183.
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Affiliation(s)
- E M Peterson
- Department of Pathology, University of California, Irvine, Irvine, California 92697-4800, USA.
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