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Abstract
Interactions between human lysozyme (HL) and the lipopolysaccharide (LPS) of Klebsiella pneumoniae O1, a causative agent of lung infection, were identified by surface plasmon resonance. To characterize the molecular mechanism of this interaction, HL binding to synthetic disaccharides and tetrasaccharides representing one and two repeating units, respectively, of the O-chain of this LPS were studied. pH-dependent structural rearrangements of HL after interaction with the disaccharide were observed through nuclear magnetic resonance. The crystal structure of the HL-tetrasaccharide complex revealed carbohydrate chain packing into the A, B, C, and D binding sites of HL, which primarily occurred through residue-specific, direct or water-mediated hydrogen bonds and hydrophobic contacts. Overall, these results support a crucial role of the Glu35/Asp53/Trp63/Asp102 residues in HL binding to the tetrasaccharide. These observations suggest an unknown glycan-guided mechanism that underlies recognition of the bacterial cell wall by lysozyme and may complement the HL immune defense function.
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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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Brogioni B, Berti F. Surface plasmon resonance for the characterization of bacterial polysaccharide antigens: a review. MEDCHEMCOMM 2014. [DOI: 10.1039/c4md00088a] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
This review gives an overview of significant applications of flow SPR to investigate the specific interactions of bacterial polysaccharide antigens.
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Johnson MA, Pinto BM. Structural and functional studies of Peptide-carbohydrate mimicry. Top Curr Chem (Cham) 2008; 273:55-116. [PMID: 23605459 DOI: 10.1007/128_2007_18] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Certain peptides act as molecular mimics of carbohydrates in that they are specifically recognizedby carbohydrate-binding proteins. Peptides that bind to anti-carbohydrate antibodies, carbohydrate-processingenzymes, and lectins have been identified. These peptides are potentially useful as vaccines andtherapeutics; for example, immunologically functional peptide molecular mimics (mimotopes) can strengthenor modify immune responses induced by carbohydrate antigens. However, peptides that bind specificallyto carbohydrate-binding proteins may not necessarily show the corresponding biological activity, andfurther selection based on biochemical studies is always required. The degree of structural mimicryrequired to generate the desired biological activity is therefore an interesting question. This reviewwill discuss recent structural studies of peptide-carbohydrate mimicry employing NMR spectroscopy,X-ray crystallography, and molecular modeling, as well as relevant biochemical data. These studiesprovide insights into the basis of mimicry at the molecular level. Comparisons with other carbohydrate-mimeticcompounds, namely proteins and glycopeptides, will be drawn. Finally, implications for the designof new therapeutic compounds will also be presented.
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Affiliation(s)
- Margaret A Johnson
- Department of Molecular Biology, The Scripps Research Institute, 10550 North Torrey Pines Rd., MB-44, 92037, La Jolla, CA, USA,
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Affiliation(s)
- Raz Jelinek
- Department of Chemistry and Staedler Minerva Center for Mesoscopic Macromolecular Engineering, Ben Gurion University of the Negev, Beersheva 84105, Israel.
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Laurent TC, Mertens P, Dierick JF, Letesson JJ, Lambert C, De Bolle X. Functional, molecular and structural characterisation of five anti-Brucella LPS mAb. Mol Immunol 2004; 40:1237-47. [PMID: 15128040 DOI: 10.1016/j.molimm.2003.11.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The O-antigen of the gram negative bacteria Brucella is composed of an homopolymer of 4,6-dideoxy-4-formamido-alpha-D-mannopyranosyl (or perosamine). Several mAb interact specifically with only the O-antigen of certain Brucella species. Although, many studies show that this specific recognition results mainly from the ratios of alpha 1-2 and alpha 1-3 link between the different Brucella strain perosamine residues, little is known about the mAb recognising this O-antigen. In this paper, we describe the binding profile of five anti-Brucella O-antigen mAb to the LPS of two Brucella strains and a bacteria possessing a nearly identical O-antigen: Yersinia enterocolitica 0:9. We show that the specificity of these five mAb can be correlated to their germ line gene usage. Besides, their relative affinity to the different LPS is correlated to their ability to protect against Brucella infection by passive transfer in a mouse model. The analysis of their 3D structure gives new hypothesis of the epitopes recognised.
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Affiliation(s)
- Thierry Cl Laurent
- Unité de Recherche en Biologie Moléculaire, Facultés Universitaires, Notre-Dame de la Paix, Rue de Bruxelles 61, B-5000 Namur, Belgium.
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Maitta RW, Datta K, Lees A, Belouski SS, Pirofski LA. Immunogenicity and efficacy of Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan peptide mimotope-protein conjugates in human immunoglobulin transgenic mice. Infect Immun 2004; 72:196-208. [PMID: 14688097 PMCID: PMC343982 DOI: 10.1128/iai.72.1.196-208.2004] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Peptide mimotopes of capsular polysaccharides have been proposed as antigens for vaccines against encapsulated pathogens. In this study, we determined the antibody response to and efficacy of P13, a peptide mimetic of the Cryptococcus neoformans capsular polysaccharide glucuronoxylomannan (GXM), in mice that produce human antibodies. P13 was conjugated to tetanus toxoid (TT) or diphtheria toxoid (DT) and administered subcutaneously in Alhydrogel with or without CpG to mice transgenic for human immunoglobulin loci (XenoMouse mice) and expressing either immunoglobulin G2 (IgG2) (G2 mice) or IgG4 (G4 mice). Mice were vaccinated and revaccinated two or three times. The serum antibody responses of the mice to GXM and P13 and antibody idiotype expression were analyzed by an enzyme-linked immunosorbent assay. The results showed that both P13-TT and P13-DT were antigenic, inducing a mimetic response to P13 in both G2 and G4 mice, and immunogenic, inducing a mimotope response including VH3 (idiotype)-positive antibodies to GXM in G2 but not G4 mice. CpG led to higher titers of IgG to P13 and GXM in P13-TT-vaccinated G2 mice. C. neoformans challenge of P13-protein conjugate-vaccinated and control G2 mice induced anamnestic IgG- and VH3-positive responses to GXM and was associated with a significantly decreased risk of death and a prolongation of survival in P13-DT-vaccinated mice compared to phosphate-buffered saline-treated or protein carrier-vaccinated mice. These findings reveal that P13 elicited a human antibody response with VH3 expression in human immunoglobulin transgenic mice that has been observed for human antibodies to GXM and support the concept that peptide mimotope-based vaccines may hold promise for the treatment of C. neoformans infections.
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Affiliation(s)
- Robert W Maitta
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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MacKenzie CR, Jennings HJ. Characterization of polysaccharide conformational epitopes by surface plasmon resonance. Methods Enzymol 2003; 363:340-54. [PMID: 14579587 DOI: 10.1016/s0076-6879(03)01063-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
SPR techniques can provide a wealth of insight into the nature of protein-carbohydrate interactions. Information not obtained readily by other methodologies can be gathered relatively quickly in a label-free manner with low sample consumption. This chapter focused on two applications in which SPR has been used to map conformational epitopes on bacterial polysaccharides recognized by protective antibodies. In one example, methods for demonstrating the conformational nature of the epitope recognized by an anti-GBS antibody were described. Dramatic epitopic stabilization at 2 repeating units with further significant stabilization between 7 and 20 repeating units was demonstrated. In a second example, SPR methods were employed in characterization of the epitope recognized by a protective antibody against the group B meningococcus. It was shown that the antibody bound a long epitope, in excess of eight monosaccharides and probably helical, on NPr-GBMP but did not bind to GBMP. The binding of the protective antibody to GBMP only when GBMP is cell associated, or with an attached lipid, indicated that the protective GBM epitope consists of more than GBMP. NPr-GBMP mimics a cell surface complex consisting of extended helical portions of the GBMP in association with a second molecule, possibly a phosphoglycerolipid. SPR experiments indicated that the protective nature of certain antibodies induced by the NPr-GBMP vaccine is attributable to their recognition of an abundant internal epitope on NPr-GBMP and cell-associated GBMP. A nonprotective antibody, specific for NPr-GBMP, recognized a terminal and consequently minor epitope on the polysaccharide. Low levels of this nonprotective antibody binding to cells and unpurified polysaccharide confirmed recognition of a minor epitope on the natural antigen as well. In contrast, a protective antibody exhibited a high level of binding to the cell-associated antigen.
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Affiliation(s)
- C Roger MacKenzie
- Institute for Biological Sciences, National Research Council of Canada, 100 Sussex Drive, Ottawa, Ontario K1A OR6, Canada
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Tanha J, Dubuc G, Hirama T, Narang SA, MacKenzie CR. Selection by phage display of llama conventional V(H) fragments with heavy chain antibody V(H)H properties. J Immunol Methods 2002; 263:97-109. [PMID: 12009207 DOI: 10.1016/s0022-1759(02)00027-3] [Citation(s) in RCA: 92] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
A llama single domain antibody (dAb) library designed and constructed to contain only heavy chain antibody variable domains (V(H)Hs) also contained a substantial number of typical conventional antibody heavy chain variable sequences (V(H)s). Panning the library against two carbohydrate-specific antibodies yielded anti-idiotypic dAbs and enriched solely for sequences from the V(H) subpopulation of the library. The conventional antibody origin of these V(H)s was confirmed by using oligonucleotide probes, specific for the enriched V(H)s, to identify the parental sequences in the message employed in library construction. Surprisingly, these V(H) dAbs, which are produced in high yield in Escherichia coli, are highly soluble, have excellent temperature stability profiles and do not display any aggregation tendencies. The very close similarity of these molecules to human V(H)s makes them potentially very useful as therapeutic dAbs.
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Affiliation(s)
- Jamshid Tanha
- Institute for Biological Sciences, National Research Council Canada, Ottawa, Ontario, Canada K1A 0R6
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Monzavi-Karbassi B, Cunto-Amesty G, Luo P, Kieber-Emmons T. Peptide mimotopes as surrogate antigens of carbohydrates in vaccine discovery. Trends Biotechnol 2002; 20:207-14. [PMID: 11943376 DOI: 10.1016/s0167-7799(02)01940-6] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Carbohydrate antigens are immune targets associated with a variety of pathogens and tumor cells. Unfortunately, most carbohydrates are intrinsically T cell-independent antigens, which diminishes their efficacy as immunogens. The conversion of carbohydrate epitopes to peptide mimotopes is one means to overcome the T cell-independent nature of carbohydrate antigens because peptides have an absolute requirement for T cells. Although such conversion has great potential for the development of veterinarian and human vaccines, there are issues related to the use of peptide-based immunogens as functional surrogates. Some of these issues are fundamental, pertaining to how mimicry comes about at the molecular level, and some are application oriented, directed at elucidating important immunological mechanisms. In this article the potential and caveats of this technology regarding its application in vaccine discovery are analyzed.
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Abstract
Vaccination is a rational alternative to treatment for Cryptococcus neoformans infections, as these infections are currently intractable in immunocompromised (including HIV-infected) individuals. Vaccines composed of the cryptococcal capsular polysaccharide glucuronoxylomannan (GXM), the key C. neoformans virulence factor, elicit protective antibodies in mice, although deleterious antibodies can also be induced. By contrast, polysaccharides are poor immunogens in HIV-infected humans and others with B-cell defects. Peptide mimotopes of GXM can induce protective immunity to C. neoformans in mice, however, our knowledge of the mechanisms of mimotope-induced protection is incomplete and further work is needed if polysaccharide- or mimotope-based vaccines are to be used to manage C. neoformans infection.
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Affiliation(s)
- L A Pirofski
- Divn of Infectious Diseases, Room 709 Forchheimer Bldg, Albert Einstein College of Medicine, 1300 Morris Park Avenue, Bronx, NY 10461, USA.
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Abstract
The application of surface plasmon resonance biosensors in life sciences and pharmaceutical research continues to increase. This review provides a comprehensive list of the commercial 1999 SPR biosensor literature and highlights emerging applications that are of general interest to users of the technology. Given the variability in the quality of published biosensor data, we present some general guidelines to help increase confidence in the results reported from biosensor analyses.
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Affiliation(s)
- R L Rich
- Center for Biomolecular Interaction Analysis, University of Utah School of Medicine, Salt Lake City 84132, USA
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Harris SL, Park MK, Nahm MH, Diamond B. Peptide mimic of phosphorylcholine, a dominant epitope found on Streptococcus pneumoniae. Infect Immun 2000; 68:5778-84. [PMID: 10992485 PMCID: PMC101537 DOI: 10.1128/iai.68.10.5778-5784.2000] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Even in the age of antibiotics, Streptococcus pneumoniae causes significant morbidity, especially in the young, the elderly, and the immunocompromised. While a carbohydrate-based vaccine exists, it is poorly immunogenic in the at-risk populations. In mice, antibodies directed against phosphorylcholine (PC), an epitope present on the cell wall C polysaccharide of all pneumococcal serotypes, protect against infection. However, PC itself is a poor vaccine candidate. We report here peptide mimics of PC based on the anti-idiotypic interaction of T15 anti-PC antibodies. T15 antibodies, the dominant and protective idiotype induced in mice by PC immunization, self-associate via a 24-amino-acid region in the PC binding site (ASRNKANDYTTEYSASVKGRFIVS; peptide 1). Peptide 1 has been shown to bind in the PC binding site. We demonstrated that amino acid sequences derived from peptide 1 starting at amino acid 9, 11, or 13 inhibit PC binding. Therefore, we immunized mice with bovine serum albumin (BSA) conjugates of peptide 1 or either of two selected 12-mers. The 12-mer peptides were not immunogenic. Mice immunized with peptide 1-BSA developed an anti-PC response consisting mainly immunoglobulin G1 and expressed the T15 heavy chain. Nonetheless, neither BALB/c nor CBA/N mice were protected from lethal pneumococcal infections by immunization with peptide 1-BSA. Preliminary data suggest that peptide 1-BSA is not able to elicit the canonical T15 light chain, explaining the absence of protection. This idiotype-derived mimotope of PC is a useful tool for understanding immunologic cross-reactivity and learning to design T-cell-dependent vaccines for S. pneumoniae.
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Affiliation(s)
- S L Harris
- Department of Microbiology and Immunology, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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