1
|
Ständer S, R Grauslund L, Scarselli M, Norais N, Rand K. Epitope Mapping of Polyclonal Antibodies by Hydrogen-Deuterium Exchange Mass Spectrometry (HDX-MS). Anal Chem 2021; 93:11669-11678. [PMID: 34308633 DOI: 10.1021/acs.analchem.1c00696] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Epitope mapping of antibodies (Abs) is crucial for understanding adaptive immunity, as well as studying the mode of action of therapeutic antibodies and vaccines. Especially insights into the binding of the entire polyclonal antibody population (pAb) raised upon vaccination would be of unique value to vaccine development. However, very few methods for epitope mapping can tolerate the complexity of a pAb sample. Here we show how hydrogen-deuterium exchange mass spectrometry (HDX-MS) can be used to map epitopes recognized by pAb samples. Our approach involves measuring the HDX of the antigen in absence or presence of varied amounts of pAbs, as well as dissociating additives. We apply the HDX-MS workflow to pAbs isolated from rabbit immunized with factor H-binding protein (fHbp), a Neisseria meningitidis vaccine antigen. We identify four immunogenic regions located on the N- and C-terminal region of fHbp and provide insights into the relative abundance and avidity of epitope binding Abs present in the sample. Overall, our results show that HDX-MS can provide a unique and relatively fast method for revealing the binding impact of the entire set of pAbs present in blood samples after vaccination. Such information provides a rare view into effective immunity and can guide the design of improved vaccines against viruses or bacteria.
Collapse
Affiliation(s)
- Susanne Ständer
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | - Laura R Grauslund
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark.,GSK, Via Fiorentina 1, 53100 Siena, Italy
| | | | | | - Kasper Rand
- Protein Analysis Group, Department of Pharmacy, University of Copenhagen, Universitetsparken 2, 2100 Copenhagen, Denmark
| |
Collapse
|
2
|
Cantini F, Banci L. Structural Knowledge for Molecular Optimization: The Cases of Metal-Mediated Protein-Protein Interactions and Structural Vaccinology. Eur J Inorg Chem 2018. [DOI: 10.1002/ejic.201800699] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Francesca Cantini
- Magnetic Resonance Center (CERM); University of Florence; Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| | - Lucia Banci
- Magnetic Resonance Center (CERM); University of Florence; Via L. Sacconi 6 50019 Sesto Fiorentino Italy
- Department of Chemistry; University of Florence; Via della Lastruccia 3 50019 Sesto Fiorentino Italy
| |
Collapse
|
3
|
Abstract
The majority of invasive meningococcal disease (IMD) in the developed world is caused by capsular group B Neisseria meningitidis, however success with vaccination against organisms bearing this capsule has previously been restricted to control of geographically limited clonal outbreaks. As we enter a new era, with the first routine program underway to control endemic group B meningococcal disease for infants in the UK, it is timely to review the key landmarks in group B vaccine development, and discuss the issues determining whether control of endemic group B disease will be achieved. Evidence of a reduction in carriage acquisition of invasive group B meningococcal strains, after vaccination among adolescents, is imperative if routine immunization is to drive population control of disease beyond those who are vaccinated (i.e. through herd immunity). The need for multiple doses to generate a sufficiently protective response and reactogenicity remain significant problems with the new generation of vaccines. Despite these limitations, early data from the UK indicate that new group B meningococcal vaccines have the potential to have a major impact on meningococcal disease, and to provide new insight into how we might do better in the future.
Collapse
Affiliation(s)
- N Y Wang
- a School of Medicine , Monash University , Melbourne , Australia.,b Department of Paediatrics , Oxford Vaccine Group , Oxford , UK
| | - A J Pollard
- b Department of Paediatrics , Oxford Vaccine Group , Oxford , UK.,c NIHR Oxford Biomedical Research Centre, University of Oxford , Oxford , UK
| |
Collapse
|
4
|
Fantappiè L, Irene C, De Santis M, Armini A, Gagliardi A, Tomasi M, Parri M, Cafardi V, Bonomi S, Ganfini L, Zerbini F, Zanella I, Carnemolla C, Bini L, Grandi A, Grandi G. Some Gram-negative Lipoproteins Keep Their Surface Topology When Transplanted from One Species to Another and Deliver Foreign Polypeptides to the Bacterial Surface. Mol Cell Proteomics 2017; 16:1348-1364. [PMID: 28483926 PMCID: PMC5500766 DOI: 10.1074/mcp.m116.065094] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 05/05/2017] [Indexed: 11/29/2022] Open
Abstract
In Gram-negative bacteria, outer membrane-associated lipoproteins can either face the periplasm or protrude out of the bacterial surface. The mechanisms involved in lipoprotein transport through the outer membrane are not fully elucidated. Some lipoproteins reach the surface by using species-specific transport machinery. By contrast, a still poorly characterized group of lipoproteins appears to always cross the outer membrane, even when transplanted from one organism to another. To investigate such lipoproteins, we tested the expression and compartmentalization in E. coli of three surface-exposed lipoproteins, two from Neisseria meningitidis (Nm-fHbp and NHBA) and one from Aggregatibacter actinomycetemcomitans (Aa-fHbp). We found that all three lipoproteins were lipidated and compartmentalized in the E. coli outer membrane and in outer membrane vesicles. Furthermore, fluorescent antibody cell sorting analysis, proteolytic surface shaving, and confocal microscopy revealed that all three proteins were also exposed on the surface of the outer membrane. Removal or substitution of the first four amino acids following the lipidated cysteine residue and extensive deletions of the C-terminal regions in Nm-fHbp did not prevent the protein from reaching the surface of the outer membrane. Heterologous polypeptides, fused to the C termini of Nm-fHbp and NHBA, were efficiently transported to the E. coli cell surface and compartmentalized in outer membrane vesicles, demonstrating that these lipoproteins can be exploited in biotechnological applications requiring Gram-negative bacterial surface display of foreign polypeptides.
Collapse
Affiliation(s)
- Laura Fantappiè
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Carmela Irene
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Micaela De Santis
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Alessandro Armini
- §Functional Proteomics Lab., Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Assunta Gagliardi
- §Functional Proteomics Lab., Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Michele Tomasi
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Matteo Parri
- ¶Toscana Life Sciences Scientific Park, Via Fiorentina, 1 53100, Siena, Italy
| | - Valeria Cafardi
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Serena Bonomi
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Luisa Ganfini
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Francesca Zerbini
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Ilaria Zanella
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy
| | - Chiara Carnemolla
- §Functional Proteomics Lab., Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Luca Bini
- §Functional Proteomics Lab., Department of Life Sciences, University of Siena, Via Aldo Moro 2, 53100 Siena, Italy
| | - Alberto Grandi
- ¶Toscana Life Sciences Scientific Park, Via Fiorentina, 1 53100, Siena, Italy
| | - Guido Grandi
- From the ‡Synthetic and Structural Vaccinology Unit, CIBIO, University of Trento, Via Sommarive, 9, 38123 Povo, Trento, Italy;
| |
Collapse
|
5
|
Molecular Engineering of Ghfp, the Gonococcal Orthologue of Neisseria meningitidis Factor H Binding Protein. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:769-77. [PMID: 25947148 DOI: 10.1128/cvi.00794-14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/18/2014] [Accepted: 04/28/2015] [Indexed: 11/20/2022]
Abstract
Knowledge of the sequences and structures of proteins produced by microbial pathogens is continuously increasing. Besides offering the possibility of unraveling the mechanisms of pathogenesis at the molecular level, structural information provides new tools for vaccine development, such as the opportunity to improve viral and bacterial vaccine candidates by rational design. Structure-based rational design of antigens can optimize the epitope repertoire in terms of accessibility, stability, and variability. In the present study, we used epitope mapping information on the well-characterized antigen of Neisseria meningitidis factor H binding protein (fHbp) to engineer its gonococcal homologue, Ghfp. Meningococcal fHbp is typically classified in three distinct antigenic variants. We introduced epitopes of fHbp variant 1 onto the surface of Ghfp, which is naturally able to protect against meningococcal strains expressing fHbp of variants 2 and 3. Heterologous epitopes were successfully transplanted, as engineered Ghfp induced functional antibodies against all three fHbp variants. These results confirm that structural vaccinology represents a successful strategy for modulating immune responses, and it is a powerful tool for investigating the extension and localization of immunodominant epitopes.
Collapse
|
6
|
Sharon J, Rynkiewicz MJ, Lu Z, Yang CY. Discovery of protective B-cell epitopes for development of antimicrobial vaccines and antibody therapeutics. Immunology 2014; 142:1-23. [PMID: 24219801 PMCID: PMC3992043 DOI: 10.1111/imm.12213] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2013] [Revised: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 01/07/2023] Open
Abstract
Protective antibodies play an essential role in immunity to infection by neutralizing microbes or their toxins and recruiting microbicidal effector functions. Identification of the protective B-cell epitopes, those parts of microbial antigens that contact the variable regions of the protective antibodies, can lead to development of antibody therapeutics, guide vaccine design, enable assessment of protective antibody responses in infected or vaccinated individuals, and uncover or localize pathogenic microbial functions that could be targeted by novel antimicrobials. Monoclonal antibodies are required to link in vivo or in vitro protective effects to specific epitopes and may be obtained from experimental animals or from humans, and their binding can be localized to specific regions of antigens by immunochemical assays. The epitopes are then identified with mapping methods such as X-ray crystallography of antigen-antibody complexes, antibody inhibition of hydrogen-deuterium exchange in the antigen, antibody-induced alteration of the nuclear magnetic resonance spectrum of the antigen, and experimentally validated computational docking of antigen-antibody complexes. The diversity in shape, size and structure of protective B-cell epitopes, and the increasing importance of protective B-cell epitope discovery to development of vaccines and antibody therapeutics are illustrated through examples from different microbe categories, with emphasis on epitopes targeted by broadly neutralizing antibodies to pathogens of high antigenic variation. Examples include the V-shaped Ab52 glycan epitope in the O-antigen of Francisella tularensis, the concave CR6261 peptidic epitope in the haemagglutinin stem of influenza virus H1N1, and the convex/concave PG16 glycopeptidic epitope in the gp120 V1/V2 loop of HIV type 1.
Collapse
MESH Headings
- Animals
- Antibodies, Bacterial/immunology
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/therapeutic use
- Antibodies, Neutralizing/immunology
- Antibodies, Neutralizing/therapeutic use
- Antibodies, Viral/immunology
- Antigen-Antibody Reactions
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/immunology
- Antigens, Viral/chemistry
- Antigens, Viral/immunology
- Bacterial Vaccines/immunology
- Bacterial Vaccines/therapeutic use
- Epitope Mapping
- Epitopes, B-Lymphocyte/chemistry
- Epitopes, B-Lymphocyte/immunology
- Humans
- Models, Molecular
- Protein Conformation
- Viral Vaccines/immunology
- Viral Vaccines/therapeutic use
Collapse
Affiliation(s)
- Jacqueline Sharon
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Michael J Rynkiewicz
- Department of Physiology and Biophysics, Boston University School of MedicineBoston, MA, USA
| | - Zhaohua Lu
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| | - Chiou-Ying Yang
- Department of Pathology and Laboratory Medicine, Boston University School of MedicineBoston, MA, USA
| |
Collapse
|
7
|
Bai X, Borrow R. Genetic shifts ofNeisseria meningitidisserogroup B antigens and the quest for a broadly cross-protective vaccine. Expert Rev Vaccines 2014; 9:1203-17. [DOI: 10.1586/erv.10.116] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
8
|
Faleri A, Santini L, Brier S, Pansegrau W, Lo Surdo P, Scarselli M, Buricchi F, Volpini G, Genovese A, van der Veen S, Lea S, Tang CM, Savino S, Pizza M, Finco O, Norais N, Masignani V. Two cross-reactive monoclonal antibodies recognize overlapping epitopes on Neisseria meningitidis factor H binding protein but have different functional properties. FASEB J 2013; 28:1644-53. [PMID: 24371123 DOI: 10.1096/fj.13-239012] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Factor H binding protein (fHbp) is one of the main antigens of the 4-component meningococcus B (4CMenB) multicomponent vaccine against disease caused by serogroup B Neisseria meningitidis (MenB). fHbp binds the complement down-regulating protein human factor H (hfH), thus resulting in immune evasion. fHbp exists in 3 variant groups with limited cross-protective responses. Previous studies have described the generation of monoclonal antibodies (mAbs) targeting variant-specific regions of fHbp. Here we report for the first time the functional characterization of two mAbs that recognize a wide panel of fHbp variants and subvariants on the MenB surface and that are able to inhibit fHbp binding to hfH. The antigenic regions targeted by the two mAbs were accurately mapped by hydrogen-deuterium exchange mass spectrometry (HDX-MS), revealing partially overlapping epitopes on the N terminus of fHbp. Furthermore, while none of the mAbs had bactericidal activity on its own, a synergistic effect was observed for each of them when tested by the human complement serum bactericidal activity (hSBA) assay in combination with a second nonbactericidal mAb. The bases underlying fHbp variant cross-reactivity, as well as inhibition of hfH binding and cooperativity effect observed for the two mAbs, are discussed in light of the mapped epitopes.
Collapse
Affiliation(s)
- Agnese Faleri
- 1Research Center, Novartis Vaccines and Diagnostics Srl, Via Fiorentina 1, 53100 Siena, Italy.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
9
|
Design of meningococcal factor H binding protein mutant vaccines that do not bind human complement factor H. Infect Immun 2012; 80:2667-77. [PMID: 22615247 DOI: 10.1128/iai.00103-12] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Meningococcal factor H binding protein (fHbp) is a human species-specific ligand for the complement regulator, factor H (fH). In recent studies, fHbp vaccines in which arginine at position 41 was replaced by serine (R41S) had impaired fH binding. The mutant vaccines elicited bactericidal responses in human fH transgenic mice superior to those elicited by control fHbp vaccines that bound human fH. Based on sequence similarity, fHbp has been classified into three variant groups. Here we report that although R41 is present in fHbp from variant groups 1 and 2, the R41S substitution eliminated fH binding only in variant group 1 proteins. To identify mutants in variant group 2 with impaired fH binding, we generated fHbp structural models and predicted 63 residues influencing fH binding. From these, we created 11 mutants with one or two amino acid substitutions in a variant group 2 protein and identified six that decreased fH binding. Three of these six mutants retained conformational epitopes recognized by all six anti-fHbp monoclonal antibodies (MAbs) tested and elicited serum complement-mediated bactericidal antibody titers in wild-type mice that were not significantly different from those obtained with the control vaccine. Thus, fHbp amino acid residues that affect human fH binding differ across variant groups. This result suggests that fHbp sequence variation induced by immune selection also affects fH binding motifs via coevolution. The three new fHbp mutants from variant group 2, which do not bind human fH, retained important epitopes for eliciting bactericidal antibodies and may be promising vaccine candidates.
Collapse
|
10
|
Giuntini S, Beernink PT, Reason DC, Granoff DM. Monoclonal antibodies to meningococcal factor H binding protein with overlapping epitopes and discordant functional activity. PLoS One 2012; 7:e34272. [PMID: 22461909 PMCID: PMC3312907 DOI: 10.1371/journal.pone.0034272] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2012] [Accepted: 02/25/2012] [Indexed: 11/20/2022] Open
Abstract
Background Meningococcal factor H binding protein (fHbp) is a promising vaccine candidate. Anti-fHbp antibodies can bind to meningococci and elicit complement-mediated bactericidal activity directly. The antibodies also can block binding of the human complement down-regulator, factor H (fH). Without bound fH, the organism would be expected to have increased susceptibility to bacteriolysis. Here we describe bactericidal activity of two anti-fHbp mAbs with overlapping epitopes in relation to their different effects on fH binding and bactericidal activity. Methods and Principal Findings Both mAbs recognized prevalent fHbp sequence variants in variant group 1. Using yeast display and site-specific mutagenesis, binding of one of the mAbs (JAR 1, IgG3) to fHbp was eliminated by a single amino acid substitution, R204A, and was decreased by K143A but not by R204H or D142A. The JAR 1 epitope overlapped that of previously described mAb (mAb502, IgG2a) whose binding to fHbp was eliminated by R204A or R204H substitutions, and was decreased by D142A but not by K143A. Although JAR 1 and mAb502 appeared to have overlapping epitopes, only JAR 1 inhibited binding of fH to fHbp and had human complement-mediated bactericidal activity. mAb502 enhanced fH binding and lacked human complement-mediated bactericidal activity. To control for confounding effects of different mouse IgG subclasses on complement activation, we created chimeric mAbs in which the mouse mAb502 or JAR 1 paratopes were paired with human IgG1 constant regions. While both chimeric mAbs showed similar binding to fHbp, only JAR 1, which inhibited fH binding, had human complement-mediated bactericidal activity. Conclusions The lack of human complement-mediated bactericidal activity by anti-fHbp mAb502 appeared to result from an inability to inhibit binding of fH. These results underscore the importance of inhibition of fH binding for anti-fHbp mAb bactericidal activity.
Collapse
MESH Headings
- Amino Acid Sequence
- Animals
- Antibodies, Monoclonal/genetics
- Antibodies, Monoclonal/immunology
- Antibodies, Monoclonal/metabolism
- Antibody Specificity/immunology
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Antigens, Bacterial/metabolism
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Bacterial Proteins/metabolism
- Bacteriolysis/immunology
- Complement Factor H/genetics
- Complement Factor H/immunology
- Complement Factor H/metabolism
- Enzyme-Linked Immunosorbent Assay
- Epitope Mapping
- Epitopes/genetics
- Epitopes/immunology
- Epitopes/metabolism
- Humans
- Meningococcal Vaccines/genetics
- Meningococcal Vaccines/immunology
- Meningococcal Vaccines/metabolism
- Mice
- Mice, Inbred BALB C
- Mice, Transgenic
- Molecular Sequence Data
- Mutagenesis, Site-Directed
- Neisseria meningitidis, Serogroup B/immunology
- Protein Binding/immunology
- Recombinant Proteins/immunology
- Recombinant Proteins/metabolism
Collapse
Affiliation(s)
| | | | | | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
- * E-mail:
| |
Collapse
|
11
|
Sanders H, Brehony C, Maiden MCJ, Vipond C, Feavers IM. The effect of iron availability on transcription of the Neisseria meningitidis fHbp gene varies among clonal complexes. MICROBIOLOGY-SGM 2012; 158:869-876. [PMID: 22241045 PMCID: PMC3949423 DOI: 10.1099/mic.0.054957-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Factor H binding protein (fHbp) is a major antigenic component of novel vaccines
designed to protect against meningococcal disease. Prediction of the potential coverage of these
vaccines is difficult, as fHbp is antigenically variable and levels of expression differ among
isolates. Transcriptional regulation of the fHbp gene is poorly understood,
although evidence suggests that oxygen availability is involved. In this study iron accessibility
was found to affect fHbp transcription. However, regulation differed among
meningococcal clonal complexes (ccs). For the majority of isolates, increased iron
concentrations upregulated transcription. This effect was enhanced by the presence of a 181 bp
insertion element upstream of fHbp, associated with isolates belonging to cc4 and
cc5. Conversely, meningococci belonging to cc32 showed iron-repressed control of
fHbp, as regulation was dominated by cotranscription with the iron-repressed
upstream gene cbbA. These results highlight the complexity of fHbp
regulation and demonstrate that control of transcription can vary among genetic lineages.
Collapse
Affiliation(s)
- Holly Sanders
- National Institute for Biological Standards and Control, Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK
| | - Carina Brehony
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Martin C J Maiden
- Department of Zoology, University of Oxford, The Tinbergen Building, South Parks Road, Oxford OX1 3PS, UK
| | - Caroline Vipond
- National Institute for Biological Standards and Control, Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK
| | - Ian M Feavers
- National Institute for Biological Standards and Control, Blanche Lane, Potters Bar, Hertfordshire EN6 3QG, UK
| |
Collapse
|
12
|
Esposito V, Musi V, de Chiara C, Veggi D, Serruto D, Scarselli M, Kelly G, Pizza M, Pastore A. Structure of the C-terminal domain of Neisseria heparin binding antigen (NHBA), one of the main antigens of a novel vaccine against Neisseria meningitidis. J Biol Chem 2011; 286:41767-41775. [PMID: 21965688 PMCID: PMC3308885 DOI: 10.1074/jbc.m111.289314] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Neisseria heparin binding antigen (NHBA), also known as GNA2132 (genome-derived Neisseria antigen 2132), is a surface-exposed lipoprotein from Neisseria meningitidis that was originally identified by reverse vaccinology. It is one the three main antigens of a multicomponent vaccine against serogroup B meningitis (4CMenB), which has just completed phase III clinical trials in infants. In contrast to the other two main vaccine components, little is known about the origin of the immunogenicity of this antigen, and about its ability to induce a strong cross-bactericidal response in animals and humans. To characterize NHBA in terms of its structural/immunogenic properties, we have analyzed its sequence and identified a C-terminal region that is highly conserved in all strains. We demonstrate experimentally that this region is independently folded, and solved its three-dimensional structure by nuclear magnetic resonance. Notably, we need detergents to observe a single species in solution. The NHBA domain fold consists of an 8-strand β-barrel that closely resembles the C-terminal domains of N. meningitidis factor H-binding protein and transferrin-binding protein B. This common fold together with more subtle structural similarities suggest a common ancestor for these important antigens and a role of the β-barrel fold in inducing immunogenicity against N. meningitidis. Our data represent the first step toward understanding the relationship between structural, functional, and immunological properties of this important vaccine component.
Collapse
Affiliation(s)
- Veronica Esposito
- MRC National Institute for Medical Research, The Ridgeway, London NW71AA, United Kingdom
| | - Valeria Musi
- MRC National Institute for Medical Research, The Ridgeway, London NW71AA, United Kingdom
| | - Cesira de Chiara
- MRC National Institute for Medical Research, The Ridgeway, London NW71AA, United Kingdom
| | - Daniele Veggi
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
| | - Davide Serruto
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
| | - Maria Scarselli
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
| | - Geoff Kelly
- MRC National Institute for Medical Research, The Ridgeway, London NW71AA, United Kingdom
| | - Mariagrazia Pizza
- Novartis Vaccines and Diagnostics, via Fiorentina 1, 53100 Siena, Italy
| | - Annalisa Pastore
- MRC National Institute for Medical Research, The Ridgeway, London NW71AA, United Kingdom.
| |
Collapse
|
13
|
Ayalew S, Shrestha B, Montelongo M, Wilson AE, Confer AW. Identification and immunogenicity of Mannheimia haemolytica S1 outer membrane lipoprotein PlpF. Vaccine 2011; 29:8712-8. [PMID: 21875637 DOI: 10.1016/j.vaccine.2011.08.074] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 07/19/2011] [Accepted: 08/15/2011] [Indexed: 11/29/2022]
Abstract
Immunity against Mannheimia haemolytica requires antibodies against leukotoxin (LKT) and bacterial cell surface antigens, most likely immunogenic outer membrane proteins (OMPs). Five immunogenic outer membrane lipoproteins identified and characterized in M. haemolytica were designated Pasteurella lipoproteins (Plp) A, -B, -C, -D and -E. Using immunoproteomics, we identified a heretofore-uncharacterized M. haemolytica immunogenic outer membrane lipoprotein that we designated PlpF, which was previously designated in the published sequence as a conserved hypothetical protein. We cloned and expressed rPlpF from two M. haemolytica serotype 1 strains (SAC159 and SAC160) and demonstrated a variable number of perfect (KKTEED) or imperfect (KKaEEa) repeats between residues 41 and 76 on the N-terminus. Antigenicity plots predicted the N-terminus repeat region to be highly antigenic. The plpF gene in multiple M. haemolytica S1, S2, and S6 isolates varied in the number of repeats from three to seven. C-terminal region was highly conserved. Immunization of mice with SAC159 or SAC160 demonstrated immunogenicity in a dose-response manner. Immunization of calves demonstrated an increase in antibodies to PlpF, and rPlpF antibodies stimulated complement-mediated killing of M. haemolytica. Because calves had pre-existing anti-M. haemolytica antibodies due to prior natural exposure, functionality of the anti-PlpF antibody responses were demonstrated by marked reduction of complement-mediated killing by blocking of anti-PlpF antibodies with rPlpF In conclusion, PlpF might have vaccination potential against M. haemolytica infection in cattle.
Collapse
Affiliation(s)
- Sahlu Ayalew
- Department of Veterinary Pathobiology, Oklahoma State University, Stillwater, OK 74078, USA.
| | | | | | | | | |
Collapse
|
14
|
Cendron L, Veggi D, Girardi E, Zanotti G. Structure of the uncomplexed Neisseria meningitidis factor H-binding protein fHbp (rLP2086). Acta Crystallogr Sect F Struct Biol Cryst Commun 2011; 67:531-5. [PMID: 21543855 PMCID: PMC3087634 DOI: 10.1107/s1744309111006154] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Accepted: 02/18/2011] [Indexed: 05/30/2023]
Abstract
fHbp, a highly immunogenic outer membrane protein of Neisseria meningitidis, is responsible for binding to human factor H, a multi-domain protein which is the central regulator of the alternative complement pathway. Here, the crystal structure of mature fHbp determined at 2 Å resolution is presented and is compared with the structure of the same protein in complex with factor H domains 6 and 7 recently solved using X-ray techniques. While the overall protein fold is well conserved, modifications are observed mainly in the loop regions involved in the interaction, reflecting a specific adaptation of fHbp in complexing factor H with high affinity. Such a comparison has to date been impaired by the fact that fHbp models determined by NMR show remarkable differences over the entire structure.
Collapse
Affiliation(s)
- Laura Cendron
- Department of Biological Chemistry, University of Padua, Viale G. Colombo 3, 35121 Padua, Italy.
| | | | | | | |
Collapse
|
15
|
Molecular mechanisms of complement evasion: learning from staphylococci and meningococci. Nat Rev Microbiol 2010; 8:393-9. [PMID: 20467445 DOI: 10.1038/nrmicro2366] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The complement system is a crucial component of the innate immune response in humans. Recent studies in Staphylococcus aureus and Neisseria meningitidis have revealed how these bacteria escape complement-mediated killing. In addition, new structural data have provided detailed insights into the molecular mechanisms of host defence mediated by the complement system and how bacterial proteins interfere with this process. This information is fundamental to our understanding of bacterial pathogenesis and may facilitate the design of better vaccines.
Collapse
|
16
|
Ayalew S, Confer AW, Hartson SD, Shrestha B. Immunoproteomic analyses of outer membrane proteins of Mannheimia haemolytica and identification of potential vaccine candidates. Proteomics 2010; 10:2151-64. [DOI: 10.1002/pmic.200900557] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
|
17
|
Roversi P, Johnson S, Lea SM. With phases: how two wrongs can sometimes make a right. ACTA CRYSTALLOGRAPHICA SECTION D: BIOLOGICAL CRYSTALLOGRAPHY 2010; 66:420-5. [PMID: 20382995 PMCID: PMC2852306 DOI: 10.1107/s0907444909048112] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2009] [Accepted: 11/12/2009] [Indexed: 11/10/2022]
Abstract
In isolation, both weak isomorphous/anomalous difference signals from heavy-atom derivatization and phases from partial molecular-replacement solutions for a subset of the asymmetric unit often fall short of producing interpretable electron-density maps. Phases generated from very partial molecular-replacement models (if generated carefully) can be used to reliably locate heavy-atom sites, even if the signal is not sufficiently strong to allow robust finding of the sites using Patterson interpretation or direct methods. Additional advantages are that using molecular-replacement phases to define the heavy-atom substructure avoids the need for subsequent hand determination and/or origin-choice reconciliation and that the partial model can be used to aid the mask determination during solvent flattening. Two case studies are presented in which it was only by combining experimental and molecular-replacement phasing approaches that the crystal structures could be determined.
Collapse
Affiliation(s)
- Pietro Roversi
- Sir William Dunn School of Pathology, University of Oxford, South Parks Road, Oxford OX1 3RE, England
| | | | | |
Collapse
|
18
|
Sadarangani M, Pollard AJ. Serogroup B meningococcal vaccines—an unfinished story. THE LANCET. INFECTIOUS DISEASES 2010; 10:112-24. [DOI: 10.1016/s1473-3099(09)70324-x] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
19
|
Brehony C, Wilson DJ, Maiden MCJ. Variation of the factor H-binding protein of Neisseria meningitidis. MICROBIOLOGY (READING, ENGLAND) 2009; 155:4155-4169. [PMID: 19729409 PMCID: PMC2801853 DOI: 10.1099/mic.0.027995-0] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/09/2009] [Revised: 08/13/2009] [Accepted: 08/27/2009] [Indexed: 12/29/2022]
Abstract
There is currently no comprehensive meningococcal vaccine, due to difficulties in immunizing against organisms expressing serogroup B capsules. To address this problem, subcapsular antigens, particularly the outer-membrane proteins (OMPs), are being investigated as candidate vaccine components. If immunogenic, however, such antigens are often antigenically variable, and knowledge of the extent and structuring of this diversity is an essential part of vaccine formulation. Factor H-binding protein (fHbp) is one such protein and is included in two vaccines under development. A survey of the diversity of the fHbp gene and the encoded protein in a representative sample of meningococcal isolates confirmed that variability in this protein is structured into two or three major groups, each with a substantial number of alleles that have some association with meningococcal clonal complexes and serogroups. A unified nomenclature scheme was devised to catalogue this diversity. Analysis of recombination and selection on the allele sequences demonstrated that parts of the gene are subject to positive selection, consistent with immune selection on the protein generating antigenic variation, particularly in the C-terminal region of the peptide sequence. The highest levels of selection were observed in regions corresponding to epitopes recognized by previously described bactericidal monoclonal antibodies.
Collapse
MESH Headings
- Alleles
- Amino Acid Sequence
- Antigens, Bacterial/chemistry
- Antigens, Bacterial/genetics
- Antigens, Bacterial/immunology
- Bacterial Proteins/chemistry
- Bacterial Proteins/genetics
- Bacterial Proteins/immunology
- Base Sequence
- DNA Primers/genetics
- DNA, Bacterial/genetics
- Genes, Bacterial
- Genetic Variation
- Humans
- Meningococcal Infections/microbiology
- Meningococcal Vaccines/genetics
- Meningococcal Vaccines/immunology
- Models, Molecular
- Molecular Sequence Data
- Neisseria meningitidis/classification
- Neisseria meningitidis/genetics
- Neisseria meningitidis/immunology
- Neisseria meningitidis, Serogroup A/classification
- Neisseria meningitidis, Serogroup A/genetics
- Neisseria meningitidis, Serogroup A/immunology
- Neisseria meningitidis, Serogroup B/classification
- Neisseria meningitidis, Serogroup B/genetics
- Neisseria meningitidis, Serogroup B/immunology
- Recombination, Genetic
- Selection, Genetic
- Sequence Homology, Amino Acid
- Serotyping
Collapse
Affiliation(s)
- Carina Brehony
- Department of Zoology, University of Oxford, OX1 3PS, UK
| | - Daniel J. Wilson
- Department of Human Genetics, University of Chicago, 920 East 58th Street, CLSC #410, Chicago, IL 60637, USA
| | | |
Collapse
|
20
|
Rinaudo CD, Telford JL, Rappuoli R, Seib KL. Vaccinology in the genome era. J Clin Invest 2009; 119:2515-25. [PMID: 19729849 DOI: 10.1172/jci38330] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Vaccination has played a significant role in controlling and eliminating life-threatening infectious diseases throughout the world, and yet currently licensed vaccines represent only the tip of the iceberg in terms of controlling human pathogens. However, as we discuss in this Review, the arrival of the genome era has revolutionized vaccine development and catalyzed a shift from conventional culture-based approaches to genome-based vaccinology. The availability of complete bacterial genomes has led to the development and application of high-throughput analyses that enable rapid targeted identification of novel vaccine antigens. Furthermore, structural vaccinology is emerging as a powerful tool for the rational design or modification of vaccine antigens to improve their immunogenicity and safety.
Collapse
|
21
|
Moraes TF, Yu RH, Strynadka NCJ, Schryvers AB. Insights into the bacterial transferrin receptor: the structure of transferrin-binding protein B from Actinobacillus pleuropneumoniae. Mol Cell 2009; 35:523-33. [PMID: 19716795 DOI: 10.1016/j.molcel.2009.06.029] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2009] [Revised: 05/09/2009] [Accepted: 06/11/2009] [Indexed: 11/17/2022]
Abstract
Pathogenic bacteria from the Neisseriaceae and Pasteurellacea families acquire iron directly from the host iron-binding glycoprotein, transferrin (Tf), in a process mediated by surface receptor proteins that directly bind host Tf, extract the iron, and transport it across the outer membrane. The bacterial Tf receptor is comprised of a surface exposed lipoprotein, Tf-binding protein B (TbpB), and an integral outer-membrane protein, Tf-binding protein A (TbpA), both of which are essential for survival in the host. In this study, we report the 1.98 A resolution structure of TbpB from the porcine pathogen Actinobacillus pleuropneumoniae, providing insights into the mechanism of Tf binding and the role of TbpB. A model for the complex of TbpB bound to Tf is proposed. Mutation of a single surface-exposed Phe residue on TbpB within the predicted interface completely abolishes binding to Tf, suggesting that the TbpB N lobe comprises the sole high-affinity binding region for Tf.
Collapse
Affiliation(s)
- Trevor F Moraes
- Department of Biochemistry and Molecular Biology, Center for Blood Research, University of British Columbia, Vancouver, BC V6T 1Z3, Canada
| | | | | | | |
Collapse
|
22
|
Zhou M, Guo Y, Zhao J, Hu Q, Hu Y, Zhang A, Chen H, Jin M. Identification and characterization of novel immunogenic outer membrane proteins of Haemophilus parasuis serovar 5. Vaccine 2009; 27:5271-7. [DOI: 10.1016/j.vaccine.2009.06.051] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2009] [Revised: 06/11/2009] [Accepted: 06/11/2009] [Indexed: 10/20/2022]
|
23
|
Abstract
The development of a comprehensive vaccine against meningococcal disease has been challenging. Recent developments in molecular genetics have provided both explanations for these challenges and possible solutions. Since genome sequence data became available there has been a marked increase in number of protein antigens that have been suggested as prospective vaccine components. This review catalogues the proposed vaccine candidates and examines the evidence for their inclusion in potential protein vaccine formulations.
Collapse
Affiliation(s)
- Ian M Feavers
- Division of Bacteriology, National Institute for Biological Standards and Control, Blanche Lane, South Mimms, Potters Bar, Hertfordshire EN6 3QG, United Kingdom.
| | | |
Collapse
|
24
|
Abstract
Complement inhibiting surface proteins of pathogenic bacteria provide candidates for vaccines because of two reasons. First, an immune response against them would recognize the microbes and secondly, it would neutralize the key bacterial virulence mechanism. Prerequisites for a vaccine protein include the following: (i) it should show limited variability, (ii) it should be immunogenic and the immune response against it should cover a sufficiently broad range of microbial strains, (iii) it should not be hidden beneath a capsule, long LPS O-polysaccharide side chains or a protein coat and (iv) it should not raise unwanted immune responses against host structures. Bacterial complement inhibitors often act by binding the soluble inhibitors factor H or C4 bp, by blocking C3 or C5 activation or by enzymatically cleaving key complement components. Inhibitors have been found from all major types of pathogens and may offer promise as rational vaccine candidates for preventing diseases such as meningococcal meningitis, systemic pneumococcal or group B streptococcal disease and Lyme borreliosis.
Collapse
|
25
|
Abstract
GNA1870, also named factor H-binding protein (fHbp) or rLP-2086, is a genome-derived antigen and one of the components of a rationally designed vaccine against Neisseria meningitidis serogroup B, which has entered phase III clinical trials. It has been classified into three main non-cross-protective variant groups. GNA1870 has also been termed fHbp because of its ability to bind factor H, a key regulatory component of the alternative complement pathway. fHbp is important for survival in human blood, human sera, and in presence of antimicrobial peptides, independently of its expression level. All these properties make fHbp a unique vaccine antigen.
Collapse
|
26
|
Schneider MC, Prosser BE, Caesar JJE, Kugelberg E, Li S, Zhang Q, Quoraishi S, Lovett JE, Deane JE, Sim RB, Roversi P, Johnson S, Tang CM, Lea SM. Neisseria meningitidis recruits factor H using protein mimicry of host carbohydrates. Nature 2009; 458:890-3. [PMID: 19225461 PMCID: PMC2670278 DOI: 10.1038/nature07769] [Citation(s) in RCA: 258] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2008] [Accepted: 01/12/2009] [Indexed: 11/08/2022]
Abstract
The complement system is an essential component of the innate and acquired immune system, and consists of a series of proteolytic cascades that are initiated by the presence of microorganisms. In health, activation of complement is precisely controlled through membrane-bound and soluble plasma-regulatory proteins including complement factor H (fH; ref. 2), a 155 kDa protein composed of 20 domains (termed complement control protein repeats). Many pathogens have evolved the ability to avoid immune-killing by recruiting host complement regulators and several pathogens have adapted to avoid complement-mediated killing by sequestering fH to their surface. Here we present the structure of a complement regulator in complex with its pathogen surface-protein ligand. This reveals how the important human pathogen Neisseria meningitidis subverts immune responses by mimicking the host, using protein instead of charged-carbohydrate chemistry to recruit the host complement regulator, fH. The structure also indicates the molecular basis of the host-specificity of the interaction between fH and the meningococcus, and informs attempts to develop novel therapeutics and vaccines.
Collapse
Affiliation(s)
- Muriel C Schneider
- Centre for Molecular Microbiology and Infection, Imperial College, London SW7 2AZ, UK
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Mascioni A, Bentley BE, Camarda R, Dilts DA, Fink P, Gusarova V, Hoiseth SK, Jacob J, Lin SL, Malakian K, McNeil LK, Mininni T, Moy F, Murphy E, Novikova E, Sigethy S, Wen Y, Zlotnick GW, Tsao DHH. Structural Basis for the Immunogenic Properties of the Meningococcal Vaccine Candidate LP2086. J Biol Chem 2009; 284:8738-46. [PMID: 19103601 PMCID: PMC2659232 DOI: 10.1074/jbc.m808831200] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2008] [Indexed: 11/06/2022] Open
Abstract
LP2086 is a family of outer membrane lipoproteins from Neisseria meningitidis, which elicits bactericidal antibodies and are currently undergoing human clinical trials in a bivalent formulation where each antigen represents one of the two known LP2086 subfamilies. Here we report the NMR structure of the recombinant LP2086 variant B01, a representative of the LP2086 subfamily B. The structure reveals a novel fold composed of two domains: a "taco-shaped" N-terminal beta-sheet and a C-terminal beta-barrel connected by a linker. The structure in micellar solution is consistent with a model of LP2086 anchored to the outer membrane bilayer through its lipidated N terminus. A long flexible chain connects the folded part of the protein to the lipid anchor and acts as spacer, making both domains accessible to the host immune system. Antibodies broadly reactive against members from both subfamilies have been mapped to the N terminus. A surface of subfamily-defining residues was identified on one face of the protein, offering an explanation for the induction of subfamily-specific bactericidal antibodies.
Collapse
Affiliation(s)
- Alessandro Mascioni
- Wyeth Research, Structural Biology and Computational Chemistry, Cambridge, Massachusetts 02140 and Wyeth Vaccines Research, Pearl River, New York 10965, USA
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Cantini F, Veggi D, Dragonetti S, Savino S, Scarselli M, Romagnoli G, Pizza M, Banci L, Rappuoli R. Solution structure of the factor H-binding protein, a survival factor and protective antigen of Neisseria meningitidis. J Biol Chem 2009; 284:9022-6. [PMID: 19196709 DOI: 10.1074/jbc.c800214200] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor H-binding protein is a 27-kDa lipoprotein of Neisseria meningitidis discovered while screening the bacterial genome for vaccine candidates. In addition to being an important component of a vaccine against meningococcus in late stage of development, the protein is essential for pathogenesis because it allows the bacterium to survive and grow in human blood by binding the human complement factor H. We recently reported the solution structure of the C-terminal domain of factor H-binding protein, which contains the immunodominant epitopes. In the present study, we report the structure of the full-length molecule, determined by nuclear magnetic resonance spectroscopy. The protein is composed of two independent barrels connected by a short link. Mapping the residues recognized by monoclonal antibodies with bactericidal or factor H binding inhibition properties allowed us to predict the sites involved in the function of the protein. The structure therefore provides the basis for designing improved vaccine molecules.
Collapse
|
29
|
Scarselli M, Cantini F, Santini L, Veggi D, Dragonetti S, Donati C, Savino S, Giuliani MM, Comanducci M, Di Marcello F, Romagnoli G, Pizza M, Banci L, Rappuoli R. Epitope mapping of a bactericidal monoclonal antibody against the factor H binding protein of Neisseria meningitidis. J Mol Biol 2008; 386:97-108. [PMID: 19100746 DOI: 10.1016/j.jmb.2008.12.005] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2008] [Revised: 11/11/2008] [Accepted: 12/02/2008] [Indexed: 10/21/2022]
Abstract
The factor H binding protein (fHbp) is a 27-kDa membrane-anchored lipoprotein of Neisseria meningitidis that allows the survival of the bacterium in human plasma; it is also a major component of a universal vaccine against meningococcus B. In this study, we used nuclear magnetic resonance spectroscopy, mutagenesis, and in silico modeling to map the epitope recognized by MAb502, a bactericidal monoclonal antibody elicited by fHbp. The data show that the antibody recognizes a conformational epitope within a well-defined area of the immunodominant C-terminal domain of the protein that is formed by two loops connecting different beta-strands of a beta-barrel and a short alpha-helix brought in spatial proximity by the protein folding. The identification of the protective epitopes of fHbp is an important factor for understanding the mechanism(s) of an effective immune response and provides valuable guidelines for designing variants of the protein able to induce broadly protective immunity.
Collapse
Affiliation(s)
- Maria Scarselli
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, 53100 Siena, Italy
| | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
30
|
Fine antigenic specificity and cooperative bactericidal activity of monoclonal antibodies directed at the meningococcal vaccine candidate factor h-binding protein. Infect Immun 2008; 76:4232-40. [PMID: 18591239 DOI: 10.1128/iai.00367-08] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
No broadly protective vaccine is available for the prevention of group B meningococcal disease. One promising candidate is factor H-binding protein (fHbp), which is present in all strains but often sparsely expressed. We prepared seven murine immunoglobulin G monoclonal antibodies (MAbs) against fHbp from antigenic variant group 2 (v.2) or v.3 ( approximately 40% of group B strains). Although none of the MAbs individually elicited bactericidal activity with human complement, all had activity in different combinations. We used MAb reactivity with strains expressing fHbp polymorphisms and site-specific mutagenesis to identify residues that are important for epitopes recognized by six of the v.2 or v.3 MAbs and by two v.1 MAbs that were previously characterized. Residues affecting v.2 or v.3 epitopes resided between amino acids 174 and 216, which formed an eight-stranded beta-barrel in the C domain, while residues affecting the v.1 epitopes included amino acids 121 and 122 of the B domain. Pairs of MAbs were bactericidal when their respective epitopes involved residues separated by 16 to 20 A and when at least one of the MAbs inhibited the binding of fH, a downregulatory complement protein. In contrast, there was no cooperative bactericidal activity when the distance between residues was >or=27 A or <or=14 A, which correlated with the inhibition of the binding of one MAb by the other MAb. Thus, a model for anti-fH MAb bactericidal activity against strains expressing low levels of fHbp requires the binding of two MAbs directed at nonoverlapping epitopes, which activates the classical complement pathway as well as inhibits fH binding. The latter increases the susceptibility of the organism to complement-mediated bacteriolysis.
Collapse
|
31
|
Bactericidal antibody responses induced by meningococcal recombinant chimeric factor H-binding protein vaccines. Infect Immun 2008; 76:2568-75. [PMID: 18362128 DOI: 10.1128/iai.00033-08] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Factor H-binding protein (fHbp) is a novel meningococcal vaccine candidate that elicits serum antibodies that activate classical complement pathway bacteriolysis and also inhibit binding of the complement down-regulatory protein, factor H, to the bacterial surface. One limitation of fHbp as a vaccine candidate is antigenic variability, since antibodies to fHbp in the variant 1 (v.1) antigenic group do not protect against strains expressing v.2 or v.3 proteins, and vice versa. We have identified amino acid residues of epitopes recognized by bactericidal anti-fHbp monoclonal antibodies prepared against fHbp from each of the variant groups. One epitope expressed by nearly all v.1 proteins mapped to the B domain, while epitopes expressed by fHbp v.2 or v.3 mapped to the C domain. The results provided the rationale for engineering chimeric fHbp molecules containing the A domain (which is conserved across all variant groups), a portion of the B domain of a v.1 protein, and the carboxyl-terminal portion of the B domain and the C domain of a v.2 protein. By enzyme-linked immunosorbent assay, the resulting recombinant chimeric proteins expressed epitopes from all three variant groups. In mice, the chimeric vaccines elicited serum antibodies with bactericidal activity against a panel of genetically diverse strains expressing fHbp v.1, v.2, or v.3. The data demonstrate the feasibility of preparing a meningococcal vaccine from a single recombinant protein that elicits broad bactericidal activity, including group B strains, which account for 50 percent of cases of meningococcal disease and for which there currently is no broadly protective vaccine.
Collapse
|
32
|
DeRocco AJ, Cornelissen CN. Identification of transferrin-binding domains in TbpB expressed by Neisseria gonorrhoeae. Infect Immun 2007; 75:3220-32. [PMID: 17438025 PMCID: PMC1932913 DOI: 10.1128/iai.00072-07] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transferrin iron acquisition system of Neisseria gonorrhoeae is necessary for iron uptake from transferrin in the human host and requires the participation of two distinct proteins: TbpA and TbpB. TbpA is a TonB-dependent outer membrane transporter responsible for the transport of iron into the cell. TbpB is a lipid-modified protein, for which a precise role in receptor function has not yet been elucidated. These receptor complex proteins show promise as vaccine candidates; therefore, it is important to identify surface-exposed regions of the proteins required for wild-type functions. In this study we examined TbpB, which has been reported to be surface exposed in its entirety; however, this hypothesis has never been tested experimentally. We placed the hemagglutinin (HA) epitope into TbpB with the dual purpose of examining the surface exposure of particular epitopes as well as their impact on receptor function. Nine insertion mutants were created, placing the epitope downstream of the signal peptidase II cleavage site. We report that the HA epitope is surface accessible in all mutants, indicating that the full-length TbpB is completely surface exposed. By expressing the TbpB-HA fusion proteins in N. gonorrhoeae, we were able to examine the impact of each insertion on the function of TbpB and the transferrin acquisition process. We propose that TbpB is comprised of two transferrin-binding-competent lobes, both of which are critical for efficient iron uptake from human transferrin.
Collapse
Affiliation(s)
- Amanda J DeRocco
- Department of Microbiology and Immunology, Virginia Commonwealth University Medical Center, Richmond, VA 23298-0678, USA
| | | |
Collapse
|
33
|
Abstract
For over a century, vaccines were developed according to Pasteur's principles of isolating, inactivating and injecting the causative agent of an infectious disease. The availability of a complete microbial genome sequence in 1995 marked the beginning of a genomic era that has allowed scientists to change the paradigm and approach vaccine development starting from genomic information, a process named reverse vaccinology. This can be considered as one of the most powerful examples of how genomic information can be used to develop therapeutic interventions, which were difficult or impossible to tackle with conventional approaches. As the genomic era progressed, it became apparent that multi-strain genome analysis is fundamental to the design of universal vaccines. In the post-genomic era, the next challenge of the vaccine biologist will be the merging of the vaccinology with structural biology.
Collapse
|