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Lo Presti A, Carannante A, Fazio C, Neri A, Vacca P, Ambrosio L, Lista F, Fillo S, Stefanelli P. FHbp variants among meningococci of serogroup B in Italy: Evolution and selective pressure, 2014-2017. PLoS One 2023; 18:e0277976. [PMID: 36795654 PMCID: PMC9934395 DOI: 10.1371/journal.pone.0277976] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 11/08/2022] [Indexed: 02/17/2023] Open
Abstract
BACKGROUND Neisseria meningitidis (meningococcus) is the causative agent of invasive meningococcal disease (IMD). Meningococcus of serogroup B (MenB) is one of the main serogroup causing IMD. MenB strains may be prevented by meningococcal B vaccines. In particular, vaccines with Factor H-binding protein (FHbp), classified into two subfamilies (A or B) or in three variants (v1, v2 or v3), are those available. The objective of the study was to investigate the phylogenetic relationships of FHbp subfamilies A and B (variants v1, v2 or v3) genes and proteins, together with their evolution patterns and selective pressure. MATERIALS AND METHODS Overall, alignments of FHbp nucleotide and protein sequence from 155 MenB samples collected in different parts of Italy, from 2014 to 2017, were analyzed by ClustalW. JModeltest and the Smart Model Selection software were used for the statistical selection of the best-fit substitution models for nucleotide and protein alignments. Site-specific positive and negative selection were estimated through the HYPHY package. The phylogenetic signal was investigated with the likelihood mapping method. The Maximum Likelihood (ML) phylogenetic reconstructions were performed with Phyml. RESULTS The phylogenic analysis identified different clusters within the FHbp subfamily A and B variants, confirming sequence diversity. The pattern of selective pressure in our study indicated that subfamily B FHbp sequences are subjected to greater variations and positive selective pressure respect to subfamily A, with 16 positively supported selected sites identified. CONCLUSION The study pointed out the need for continued genomic surveillance for meningococci to monitor selective pressure and amino acidic changes. Monitoring the genetic diversity and molecular evolution of FHbp variants may be useful to investigate genetic diversity which may emerge over time.
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Affiliation(s)
| | - Anna Carannante
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Cecilia Fazio
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Arianna Neri
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Paola Vacca
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | - Luigina Ambrosio
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
| | | | - Silvia Fillo
- Scientific Department, Army Medical Center, Rome, Italy
| | - Paola Stefanelli
- Department of Infectious Diseases, Istituto Superiore di Sanità, Rome, Italy
- * E-mail:
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Mat Rani NNI, Alzubaidi ZM, Butt AM, Mohammad Faizal NDF, Sekar M, Azhari H, Mohd Amin MCI. Outer membrane vesicles as biomimetic vaccine carriers against infections and cancers. WILEY INTERDISCIPLINARY REVIEWS. NANOMEDICINE AND NANOBIOTECHNOLOGY 2022; 14:e1784. [PMID: 35194964 DOI: 10.1002/wnan.1784] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Revised: 01/18/2022] [Accepted: 02/03/2022] [Indexed: 06/14/2023]
Abstract
In the last decade, nanoparticle-based therapeutic modalities have emerged as promising treatment options for cancer and infectious diseases. To improve prognosis, chemotherapeutic and antimicrobial drugs must be delivered selectively to the target sites. Researchers have increasingly focused their efforts on improving drug delivery, with a particular emphasis on cancer and infectious diseases. When drugs are administered systemically, they become diluted and can diffuse to all tissues but only until the immune system intervenes and quickly removes them from circulation. To enhance and prolong the systemic circulation of drugs, nanocarriers have been explored and used; however, nanocarriers have a major drawback in that they can trigger immune responses. Numerous nanocarriers for optimal drug delivery have been developed using innovative and effective biointerface technologies. Autologous cell-derived drug carriers, such as outer membrane vesicles (OMVs), have demonstrated improved bioavailability and reduced toxicity. Thus, this study investigates the use of biomimetic OMVs as biomimetic vaccine carriers against infections and cancers to improve our understanding in the field of nanotechnology. In addition, discussion on the advantages, disadvantages, and future prospects of OMVs will also be explored. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Therapeutic Approaches and Drug Discovery > Nanomedicine for Infectious Disease Biology-Inspired Nanomaterials > Protein and Virus-Based Structures.
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Affiliation(s)
- Nur Najihah Izzati Mat Rani
- Centre for Drug Delivery Technology, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia
- Faculty of Pharmacy and Health Sciences, Royal College of Medicine Perak, Universiti Kuala Lumpur, Ipoh, Perak, Malaysia
| | - Zahraa M Alzubaidi
- Centre for Drug Delivery Technology, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia
| | - Adeel Masood Butt
- Institute of Pharmaceutical Sciences, University of Veterinary and Animal Sciences, Lahore, Pakistan
| | - Nur Dini Fatini Mohammad Faizal
- Centre for Drug Delivery Technology, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia
| | - Mahendran Sekar
- Department of Pharmaceutical Chemistry, Faculty of Pharmacy and Health Sciences, Royal College of Medicine Perak, Universiti Kuala Lumpur, Ipoh, Perak, Malaysia
| | - Hanisah Azhari
- Centre for Drug Delivery Technology, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia
| | - Mohd Cairul Iqbal Mohd Amin
- Centre for Drug Delivery Technology, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, Kuala Lumpur, Malaysia
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Veggi D, Malito E, Lo Surdo P, Pansegrau W, Rippa V, Wahome N, Savino S, Masignani V, Pizza M, Bottomley MJ. Structural characterization of a cross-protective natural chimera of factor H binding protein from meningococcal serogroup B strain NL096. Comput Struct Biotechnol J 2022; 20:2070-2081. [PMID: 35601959 PMCID: PMC9079162 DOI: 10.1016/j.csbj.2022.04.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 04/11/2022] [Accepted: 04/11/2022] [Indexed: 11/25/2022] Open
Abstract
Invasive meningococcal disease can cause fatal sepsis and meningitis and is a global health threat. Factor H binding protein (fHbp) is a protective antigen included in the two currently available vaccines against serogroup B meningococcus (MenB). FHbp is a remarkably variable surface-exposed meningococcal virulence factor with over 1300 different amino acid sequences identified so far. Based on this variability, fHbp has been classified into three variants, two subfamilies or nine modular groups, with low degrees of cross-protective activity. Here, we report the crystal structure of a natural fHbp cross-variant chimera, named variant1-2,3.x expressed by the MenB clinical isolate NL096, at 1.2 Å resolution, the highest resolution of any fHbp structure reported to date. We combined biochemical, site-directed mutagenesis and computational biophysics studies to deeply characterize this rare chimera. We determined the structure to be composed of two adjacent domains deriving from the three variants and determined the molecular basis of its stability, ability to bind Factor H and to adopt the canonical three-dimensional fHbp structure. These studies guided the design of loss-of-function mutations with potential for even greater immunogenicity. Moreover, this study represents a further step in the understanding of the fHbp biological and immunological evolution in nature. The chimeric variant1-2,3.x fHbp protein emerges as an intriguing cross-protective immunogen and suggests that identification of such naturally occurring hybrid proteins may result in stable and cross-protective immunogens when seeking to design and develop vaccines against highly variable pathogens.
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Affiliation(s)
- Daniele Veggi
- Corresponding author at: GSK Vaccines srl, Via Fiorentina 1, Siena 53100, Italy.
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Moore SR, Menon SS, Cortes C, Ferreira VP. Hijacking Factor H for Complement Immune Evasion. Front Immunol 2021; 12:602277. [PMID: 33717083 PMCID: PMC7947212 DOI: 10.3389/fimmu.2021.602277] [Citation(s) in RCA: 42] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 01/15/2021] [Indexed: 12/15/2022] Open
Abstract
The complement system is an essential player in innate and adaptive immunity. It consists of three pathways (alternative, classical, and lectin) that initiate either spontaneously (alternative) or in response to danger (all pathways). Complement leads to numerous outcomes detrimental to invaders, including direct killing by formation of the pore-forming membrane attack complex, recruitment of immune cells to sites of invasion, facilitation of phagocytosis, and enhancement of cellular immune responses. Pathogens must overcome the complement system to survive in the host. A common strategy used by pathogens to evade complement is hijacking host complement regulators. Complement regulators prevent attack of host cells and include a collection of membrane-bound and fluid phase proteins. Factor H (FH), a fluid phase complement regulatory protein, controls the alternative pathway (AP) both in the fluid phase of the human body and on cell surfaces. In order to prevent complement activation and amplification on host cells and tissues, FH recognizes host cell-specific polyanionic markers in combination with complement C3 fragments. FH suppresses AP complement-mediated attack by accelerating decay of convertases and by helping to inactivate C3 fragments on host cells. Pathogens, most of which do not have polyanionic markers, are not recognized by FH. Numerous pathogens, including certain bacteria, viruses, protozoa, helminths, and fungi, can recruit FH to protect themselves against host-mediated complement attack, using either specific receptors and/or molecular mimicry to appear more like a host cell. This review will explore pathogen complement evasion mechanisms involving FH recruitment with an emphasis on: (a) characterizing the structural properties and expression patterns of pathogen FH binding proteins, as well as other strategies used by pathogens to capture FH; (b) classifying domains of FH important in pathogen interaction; and (c) discussing existing and potential treatment strategies that target FH interactions with pathogens. Overall, many pathogens use FH to avoid complement attack and appreciating the commonalities across these diverse microorganisms deepens the understanding of complement in microbiology.
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Affiliation(s)
- Sara R Moore
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Smrithi S Menon
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
| | - Claudio Cortes
- Department of Foundational Medical Sciences, Oakland University William Beaumont School of Medicine, Rochester, MI, United States
| | - Viviana P Ferreira
- Department of Medical Microbiology and Immunology, University of Toledo College of Medicine and Life Sciences, Toledo, OH, United States
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5
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Lo Passo C, Zippilli L, Angiolillo A, Costa I, Pernice I, Galbo R, Felici F, Beernink PT. Molecular characterization of two sub-family specific monoclonal antibodies to meningococcal Factor H binding protein. Heliyon 2018; 4:e00591. [PMID: 29644339 PMCID: PMC5889710 DOI: 10.1016/j.heliyon.2018.e00591] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Revised: 03/07/2018] [Accepted: 03/27/2018] [Indexed: 11/29/2022] Open
Abstract
Factor H binding protein (FHbp) is a component of two licensed vaccines for prevention of sepsis and meningitis caused by serogroup B meningococci. FHbp binds human Factor H (FH), which contributes to evasion of host immunity and FHbp sequence variants can be classified into two sub-families. Antibodies against FHbp elicit complement-mediated killing and can inhibit recruitment of FH to the bacterial surface. We report epitope mapping studies of two murine IgG mAbs, designated JAR 31 and JAR 36, isolated from a mouse immunized with FHbp in sub-family A, which is present in ∼30-40% of invasive isolates. In the present study, we tested the reactivity of mAbs JAR 31 and JAR 36 with seven natural FHbp sequence variants from different phylogenic groups. We screened bacteriophage-displayed peptide libraries to identify amino acid residues contributing to the JAR 36 epitope. Based on the reactivities of mAbs JAR 31 and JAR 36 with the seven FHbp variants, and the frequent occurrences of aspartate (D) and lysine (K) residues in the JAR 36-bound phage peptides, we selected six residues in the carboxyl-terminal region of FHbp for replacement with alanine (A). The D201A and K203A substitutions respectively eliminated and decreased binding of mAbs JAR 31 and JAR 36 to FHbp. These substitutions did not affect binding of the control mAb JAR 33 or of human FH. JAR 31 or JAR 36 mediated cooperative complement-mediated bactericidal activity with other anti-FHbp mAbs. The identification of two amino acid residues involved in the epitopes recognized by these anti-FHbp mAbs may contribute to a more complete understanding of the spatial requirements for cooperative anti-FHbp mAb bactericidal activity.
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Affiliation(s)
- C Lo Passo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - L Zippilli
- Department of Biosciences and Territory, University of Molise, Pesche (CB), Italy
| | - A Angiolillo
- Department of Medicine and Health Sciences, University of Molise, Campobasso, Italy
| | - I Costa
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - I Pernice
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - R Galbo
- Department of Chemical, Biological, Pharmaceutical and Environmental Sciences, University of Messina, Italy
| | - F Felici
- Department of Biosciences and Territory, University of Molise, Pesche (CB), Italy
| | - P T Beernink
- Center for Immunobiology and Vaccine Development, UCSF Benioff Children's Hospital Oakland, Oakland, CA, USA.,Department of Pediatrics, School of Medicine, University of California, San Francisco, USA
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6
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Contribution of factor H-Binding protein sequence to the cross-reactivity of meningococcal native outer membrane vesicle vaccines with over-expressed fHbp variant group 1. PLoS One 2017; 12:e0181508. [PMID: 28742866 PMCID: PMC5526518 DOI: 10.1371/journal.pone.0181508] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Accepted: 07/03/2017] [Indexed: 12/31/2022] Open
Abstract
Factor H-binding protein (fHbp) is an important meningococcal vaccine antigen. Native outer membrane vesicles with over-expressed fHbp (NOMV OE fHbp) have been shown to induce antibodies with broader functional activity than recombinant fHbp (rfHbp). Improved understanding of this broad coverage would facilitate rational vaccine design. We performed a pair-wise analysis of 48 surface-exposed amino acids involved in interacting with factor H, among 383 fHbp variant group 1 sequences. We generated isogenic NOMV-producing meningococcal strains from an African serogroup W isolate, each over-expressing one of four fHbp variant group 1 sequences (ID 1, 5, 9, or 74), including those most common among invasive African meningococcal isolates. Mice were immunised with each NOMV, and sera tested for IgG levels against each of the rfHbp ID and for ability to kill a panel of heterologous meningococcal isolates. At the fH-binding site, ID pairs differed by a maximum of 13 (27%) amino acids. ID 9 shared an amino acid sequence common to 83 ID types. The selected ID types differed by up to 6 amino acids, in the fH-binding site. All NOMV and rfHbp induced high IgG levels against each rfHbp. Serum killing from mice immunised with rfHbp was generally less efficient and more restricted compared to NOMV, which induced antibodies that killed most meningococci tested, with decreased stringency for ID type differences. Breadth of killing was mostly due to anti-fHbp antibodies, with some restriction according to ID type sequence differences. Nevertheless, under our experimental conditions, no relationship between antibody cross-reactivity and variation fH-binding site sequence was identified. NOMV over-expressing different fHbp IDs belonging to variant group 1 induce antibodies with fine specificities against fHbp, and ability to kill broadly meningococci expressing heterologous fHbp IDs. The work reinforces that meningococcal NOMV with OE fHbp is a promising vaccine strategy, and provides a basis for rational selection of antigen sequence types for over-expression on NOMV.
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7
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Bandehpour M, Yarian F, Ahangarzadeh S. Bioinformatics evaluation of novel ribosome display-selected single chain variable fragment (scFv) structure with factor H binding protein through docking. JOURNAL OF THEORETICAL & COMPUTATIONAL CHEMISTRY 2017. [DOI: 10.1142/s0219633617500213] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Antibodies play a significant role in the immunotherapy, basic research and the pharmaceutical industry. Nowadays, both DNA recombinant technology and antibody engineering technology are widely used in many fields such as diagnostics, therapeutics, drug targeted delivery, and research reagents. Computational docking of antigen-antibody complexes and analysis of atomic interactions are important to find effective B-cell epitopes and new antibodies with appropriate properties. In the present study, by using ClusPro 2.0 webserver, docking the antigen (factor H binding protein (fHbp)) to the novel-selected scFv antibody was performed. By analyzing the fHbp-scFv complexes, important amino acids were identified. After docking, peptides Ala192-His198, Asp 211-216, and Gly229-Ser228 of the fHbp antigen were recognized as essential interactive regions to the scFv antibody. Results obtained from our bioinformatics study are important and give us the basis for the favored designs of new molecules such as effective B-cell epitopes targeted by neutralizing antibodies for vaccine design.
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Affiliation(s)
- Mojgan Bandehpour
- Cellular & Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Fatemeh Yarian
- Cellular & Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Shahrzad Ahangarzadeh
- Cellular & Molecular Biology Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran
- Department of Biotechnology, School of Advanced Technologies in Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
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da Silva RAG, Churchward CP, Karlyshev AV, Eleftheriadou O, Snabaitis AK, Longman MR, Ryan A, Griffin R. The role of apolipoprotein N-acyl transferase, Lnt, in the lipidation of factor H binding protein of Neisseria meningitidis strain MC58 and its potential as a drug target. Br J Pharmacol 2016; 174:2247-2260. [PMID: 27784136 DOI: 10.1111/bph.13660] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 10/06/2016] [Accepted: 10/13/2016] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE The level of cell surface expression of the meningococcal vaccine antigen, Factor H binding protein (FHbp) varies between and within strains and this limits the breadth of strains that can be targeted by FHbp-based vaccines. The molecular pathway controlling expression of FHbp at the cell surface, including its lipidation, sorting to the outer membrane and export, and the potential regulation of this pathway have not been investigated until now. This knowledge will aid our evaluation of FHbp vaccines. EXPERIMENTAL APPROACH A meningococcal transposon library was screened by whole cell immuno-dot blotting using an anti-FHbp antibody to identify a mutant with reduced binding and the disrupted gene was determined. KEY RESULTS In a mutant with markedly reduced binding, the transposon was located in the lnt gene which encodes apolipoprotein N-acyl transferase, Lnt, responsible for the addition of the third fatty acid to apolipoproteins prior to their sorting to the outer membrane. We provide data indicating that in the Lnt mutant, FHbp is diacylated and its expression within the cell is reduced 10 fold, partly due to inhibition of transcription. Furthermore the Lnt mutant showed 64 fold and 16 fold increase in susceptibility to rifampicin and ciprofloxacin respectively. CONCLUSION AND IMPLICATIONS We speculate that the inefficient sorting of diacylated FHbp in the meningococcus results in its accumulation in the periplasm inducing an envelope stress response to down-regulate its expression. We propose Lnt as a potential novel drug target for combination therapy with antibiotics. LINKED ARTICLES This article is part of a themed section on Drug Metabolism and Antibiotic Resistance in Micro-organisms. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v174.14/issuetoc.
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Affiliation(s)
- R A G da Silva
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - C P Churchward
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A V Karlyshev
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - O Eleftheriadou
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A K Snabaitis
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - M R Longman
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - A Ryan
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
| | - R Griffin
- School of Life Sciences, Pharmacy and Chemistry, Kingston University, Kingston upon Thames, UK
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9
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Meningococcal Factor H Binding Protein Vaccine Antigens with Increased Thermal Stability and Decreased Binding of Human Factor H. Infect Immun 2016; 84:1735-1742. [PMID: 27021245 DOI: 10.1128/iai.01491-15] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2015] [Accepted: 03/21/2016] [Indexed: 11/20/2022] Open
Abstract
Neisseria meningitidis causes cases of bacterial meningitis and sepsis. Factor H binding protein (FHbp) is a component of two licensed meningococcal serogroup B vaccines. FHbp recruits the complement regulator factor H (FH) to the bacterial surface, which inhibits the complement alternative pathway and promotes immune evasion. Binding of human FH impairs the protective antibody responses to FHbp, and mutation of FHbp to decrease binding of FH can increase the protective responses. In a previous study, we identified two amino acid substitutions in FHbp variant group 2 that increased its thermal stability by 21°C and stabilized epitopes recognized by protective monoclonal antibodies (MAbs). Our hypothesis was that combining substitutions to increase stability and decrease FH binding would increase protective antibody responses in the presence of human FH. In the present study, we generated four new FHbp single mutants that decreased FH binding and retained binding of anti-FHbp MAbs and immunogenicity in wild-type mice. From these mutants, we selected two, K219N and G220S, to combine with the stabilized double-mutant FHbp antigen. The two triple mutants decreased FH binding >200-fold, increased the thermal stability of the N-terminal domain by 21°C, and bound better to an anti-FHbp MAb than the wild-type FHbp. In human-FH-transgenic mice, the FHbp triple mutants elicited 8- to 15-fold-higher protective antibody responses than the wild-type FHbp antigen. Collectively, the data suggest that mutations to eliminate binding of human FH and to promote conformational stability act synergistically to optimize FHbp immunogenicity.
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10
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Xu N, Wang Y, Ma J, Jin L, Xing S, Jiang C, Li X. Over-expression of fHbp in Arabdopsis for development of meningococcal serogroup B subunit vaccine. Biotechnol J 2016; 11:973-80. [PMID: 27119621 DOI: 10.1002/biot.201500656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Revised: 02/27/2016] [Accepted: 04/19/2016] [Indexed: 01/04/2023]
Abstract
Due to lack of commercial vaccine against the serogroup B (MenB) of Neisseria meningitides, the incidence of meningococcal disease remains high. To solve the issue, transgenic plants are used as bioreactors to produce a plant-derived fHbp subunit vaccine. In this study, the fHbp gene was optimized according to the codon usage bias of Arabidopsis thaliana, synthesized artificially, cloned into an expression vector, driven by a seed-specific promoter, and introduced into A. thaliana by Agrobacterium-mediated floral-dip transformation. Transgenic plants were identified by glufosinate selection, quickstix strips for PAT/bar tests and PCR analysis. The five plants showing higher expression of recombinant fHbp were screened through indirect ELISA. Southern blot analysis showed that the transgenic line rHF-22 had a single-copy integration and the highest expression of fHbp. Recombinant fHbp was purified from seeds of rHF-22 by nitrilotriacetic acid-mediated affinity chromatography, and the purity was 82.5%. BALB/c mice were tested for fHbp vaccine protection from lethal MenB infection, and the relative percent survival was found to be 80%. This study indicates that the recombinant fHbp produced from seeds of rHF-22 is a potential candidate for commercial MenB vaccine. It also provides a reference for safe, cheap and large-scale production of other plant-made vaccines.
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Affiliation(s)
- Nuo Xu
- College of Life Sciences, Jilin University, Changchun, China.,Wenzhou University, Wenzhou, China
| | - Yunpeng Wang
- Agro-Biotechnology Research Institute, Jilin Academy of Agriculture Science, Changchun, China.,Wenzhou University, Wenzhou, China.,School of Pharmaceutical Sciences, Zhejiang Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Jisheng Ma
- School of Pharmaceutical Sciences, Zhejiang Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Libo Jin
- Wenzhou University, Wenzhou, China.,School of Pharmaceutical Sciences, Zhejiang Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, China
| | - Shaochen Xing
- Agro-Biotechnology Research Institute, Jilin Academy of Agriculture Science, Changchun, China
| | - Chao Jiang
- Wenzhou University, Wenzhou, China. .,School of Pharmaceutical Sciences, Zhejiang Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, China.
| | - Xiaokun Li
- College of Life Sciences, Jilin University, Changchun, China. .,Wenzhou University, Wenzhou, China. .,School of Pharmaceutical Sciences, Zhejiang Key Laboratory of Biotechnology and Pharmaceutical Engineering, Wenzhou Medical University, Wenzhou, China.
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11
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Konar M, Pajon R, Beernink PT. A meningococcal vaccine antigen engineered to increase thermal stability and stabilize protective epitopes. Proc Natl Acad Sci U S A 2015; 112:14823-8. [PMID: 26627237 PMCID: PMC4672778 DOI: 10.1073/pnas.1507829112] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Factor H binding protein (FHbp) is part of two vaccines recently licensed for prevention of sepsis and meningitis caused by serogroup B meningococci. FHbp is classified in three phylogenic variant groups that have limited antigenic cross-reactivity, and FHbp variants in one of the groups have low thermal stability. In the present study, we replaced two amino acid residues, R130 and D133, in a stable FHbp variant with their counterparts (L and G) from a less stable variant. The single and double mutants decreased thermal stability of the amino- (N-) terminal domain compared with the wild-type protein as measured by scanning calorimetry. We introduced the converse substitutions, L130R and G133D, in a less stable wild-type FHbp variant, which increased the transition midpoint (Tm) for the N-terminal domain by 8 and 12 °C; together the substitutions increased the Tm by 21 °C. We determined the crystal structure of the double mutant FHbp to 1.6 Å resolution, which showed that R130 and D133 mediated multiple electrostatic interactions. Monoclonal antibodies specific for FHbp epitopes in the N-terminal domain had higher binding affinity for the recombinant double mutant by surface plasmon resonance and to the mutant expressed on meningococci by flow cytometry. The double mutant also had decreased binding of human complement Factor H, which in previous studies increased the protective antibody responses. The stabilized mutant FHbp thus has the potential to stabilize protective epitopes and increase the protective antibody responses to recombinant FHbp vaccines or native outer membrane vesicle vaccines with overexpressed FHbp.
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Affiliation(s)
- Monica Konar
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, CA 94609
| | - Rolando Pajon
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, CA 94609
| | - Peter T Beernink
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, University of California San Francisco Benioff Children's Hospital Oakland, Oakland, CA 94609
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Susceptibility of Meningococcal Strains Responsible for Two Serogroup B Outbreaks on U.S. University Campuses to Serum Bactericidal Activity Elicited by the MenB-4C Vaccine. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2015; 22:1227-34. [PMID: 26424832 DOI: 10.1128/cvi.00474-15] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 09/28/2015] [Indexed: 12/12/2022]
Abstract
In 2013 and 2014, two U.S. universities had meningococcal serogroup B outbreaks (a total of 14 cases) caused by strains from two different clonal complexes. To control the outbreaks, students were immunized with a serogroup B meningococcal vaccine (Novartis) that was not yet licensed in the United States. The vaccine (referred to as MenB-4C) contains four components capable of eliciting bactericidal activity. Both outbreak strains had high expression levels of two of the vaccine antigens (subfamily B factor H binding protein [FHbp] and neisserial heparin binding antigen [NHba]); the university B outbreak strain also had moderate expression of a third antigen, NadA. We investigated the bactericidal activity of sera from mice immunized with FHbp, NHba, or NadA and sera from MenB-4C-immunized infant macaques and an adult human. The postimmunization bactericidal activity of the macaque or human serum against isolates from university B with FHbp identification (ID) 1 that exactly matched the vaccine FHbp sequence variant was 8- to 21-fold higher than that against isolates from university A with FHbp ID 276 (96% identity to the vaccine antigen). Based on the bactericidal activity of mouse antisera to FHbp, NadA, or NHba and macaque or human postimmunization serum that had been depleted of anti-FHbp antibody, the bactericidal activity against both outbreak strains largely or entirely resulted from antibodies to FHbp. Thus, despite the high level of strain expression of FHbp from a subfamily that matched the vaccine antigen, there can be large differences in anti-FHbp bactericidal activity induced by MenB-4C vaccination. Further, strains with moderate to high NadA and/or NHba expression can be resistant to anti-NadA or anti-NHba bactericidal activity elicited by MenB-4C vaccination.
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Konar M, Beernink PT, Granoff DM. A Newly-Identified Polymorphism in Rhesus Macaque Complement Factor H Modulates Binding Affinity for Meningococcal FHbp. PLoS One 2015; 10:e0135996. [PMID: 26285122 PMCID: PMC4540320 DOI: 10.1371/journal.pone.0135996] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2015] [Accepted: 07/28/2015] [Indexed: 01/22/2023] Open
Abstract
Background Two meningococcal serogroup B vaccines contain Factor H binding protein (FHbp). Binding of Factor H (FH) to FHbp was thought to be specific for human or chimpanzee FH. However, in a previous study an amino acid polymorphism in rhesus macaque FH domain 6, tyrosine at position 352 (Y352) was associated with high binding to FHbp, whereas histidine at position 352 (H352) was associated with low binding. Methods and Results Here we report that a second FH polymorphism at position 360 also affects macaque FH binding. Of 43 macaques, 11 had high FH binding and 32 had low binding. As in our previous study, all 11 animals with high binding had Y352, and 24 with low binding had H352. However the remaining eight with low FH binding had Y352, which was predicted to yield high binding. All eight had S360 instead of P360. Thus, three allelic variants at positions 352 and 360 affect macaque FH binding to FHbp: HP (low), YS (low), and YP (high). We measured binding affinity of each FH sequence type to FHbp by surface plasmon resonance. Two animals with high binding types (YS/YP and HP/YP) had dissociation constants (KD) of 10.4 and 18.2 nM, respectively, which were similar to human FH (19.8 nM). Two macaques with low binding (HP/HP and HP/YS) had KD values approximately five-fold higher (100.3 and 99.5 nM, respectively). A third macaque with low binding (YS/YS) had a KD value too high to be measured. Conclusions Macaques have at least three allelic variants encoding FH with different affinities for FHbp (five genotypic combinations of these variants). Since in previous studies binding of FH to FHbp vaccines decreased protective antibody responses, our data will aid in selection of macaques with FH binding that is similar to humans for further investigation of FHbp vaccine immunogenicity.
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Affiliation(s)
- Monica Konar
- Center for Immunobiology and Vaccine Development, UCSF Benioff Children’s Hospital Oakland, Oakland, California, United States of America
| | - Peter T. Beernink
- Center for Immunobiology and Vaccine Development, UCSF Benioff Children’s Hospital Oakland, Oakland, California, United States of America
| | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, UCSF Benioff Children’s Hospital Oakland, Oakland, California, United States of America
- * E-mail:
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Abstract
Two licensed serogroup B meningococcal vaccines contain factor H binding protein (FHbp). The antigen specifically binds human FH, which downregulates complement. In wild-type mice whose mouse FH does not bind to FHbp vaccines, the serum anti-FHbp antibody response inhibited binding of human FH to FHbp. The inhibition was important for eliciting broad anti-FHbp serum bactericidal activity. In human FH transgenic mice and some nonhuman primates, FHbp was able to form a complex with FH and FHbp vaccination elicited anti-FHbp antibodies that did not inhibit FH binding. To investigate the human anti-FHbp repertoire, we cloned immunoglobulin heavy- and light-chain-variable-region genes of individual B cells from three adults immunized with FHbp vaccines and generated 10 sequence-distinct native anti-FHbp antibody fragments (Fabs). All 10 Fabs bound to live meningococci; only 1 slightly inhibited binding of human FH, while 4 enhanced FH binding. Affinity-purified anti-FHbp antibody from serum of a fourth immunized adult also enhanced binding of human FH to live meningococcal bacteria. Despite the bound FH, the affinity-purified serum anti-FHbp antibodies elicited human complement-mediated bactericidal activity that was amplified by the alternative pathway. The lack of FH inhibition by the human anti-FHbp Fabs and serum antibodies suggests that binding of human FH to the vaccine antigen skews the anti-FHbp antibody repertoire to epitopes outside the FH-binding site. Mutant FHbp vaccines with decreased FH binding may represent a means to redirect the human antibody repertoire to epitopes within the FH binding site, which can inhibit FH binding and, potentially, increase safety and protective activity. Two meningococcal vaccines contain factor H binding protein (FHbp). Immunized mice whose mouse factor H (FH) does not bind to FHbp develop serum anti-FHbp antibodies that block binding of human FH to the bacteria. With less bound FH, the bacteria become more susceptible to complement killing. To investigate human responses, we isolated 10 recombinant anti-FHbp antibody fragments (Fabs) from immune cells of three immunized adults. One slightly inhibited binding of FH to the bacteria, and four enhanced FH binding. Purified serum anti-FHbp antibodies from a fourth immunized adult also enhanced FH binding. Although bound FH would be expected to block the alternative pathway, the human anti-FHbp antibodies retained bactericidal activity and the ability to activate the alternative pathway. Mutant FHbp vaccines with decreased binding to human FH may redirect the human antibody repertoire to epitopes within the FH binding site that inhibit FH binding, which are expected to increase protective activity.
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A Mutant Library Approach to Identify Improved Meningococcal Factor H Binding Protein Vaccine Antigens. PLoS One 2015; 10:e0128185. [PMID: 26057742 PMCID: PMC4461315 DOI: 10.1371/journal.pone.0128185] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 04/23/2015] [Indexed: 01/14/2023] Open
Abstract
Factor H binding protein (FHbp) is a virulence factor used by meningococci to evade the host complement system. FHbp elicits bactericidal antibodies in humans and is part of two recently licensed vaccines. Using human complement Factor H (FH) transgenic mice, we previously showed that binding of FH decreased the protective antibody responses to FHbp vaccination. Therefore, in the present study we devised a library-based method to identify mutant FHbp antigens with very low binding of FH. Using an FHbp sequence variant in one of the two licensed vaccines, we displayed an error-prone PCR mutant FHbp library on the surface of Escherichia coli. We used fluorescence-activated cell sorting to isolate FHbp mutants with very low binding of human FH and preserved binding of control anti-FHbp monoclonal antibodies. We sequenced the gene encoding FHbp from selected clones and introduced the mutations into a soluble FHbp construct. Using this approach, we identified several new mutant FHbp vaccine antigens that had very low binding of FH as measured by ELISA and surface plasmon resonance. The new mutant FHbp antigens elicited protective antibody responses in human FH transgenic mice that were up to 20-fold higher than those elicited by the wild-type FHbp antigen. This approach offers the potential to discover mutant antigens that might not be predictable even with protein structural information and potentially can be applied to other microbial vaccine antigens that bind host proteins.
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Panatto D, Amicizia D, Lai PL, Gasparini R. Neisseria meningitidisB vaccines. Expert Rev Vaccines 2014; 10:1337-51. [DOI: 10.1586/erv.11.103] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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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.
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Affiliation(s)
- Agnese Faleri
- 1Research Center, Novartis Vaccines and Diagnostics Srl, Via Fiorentina 1, 53100 Siena, Italy.
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Distinct binding and immunogenic properties of the gonococcal homologue of meningococcal factor h binding protein. PLoS Pathog 2013; 9:e1003528. [PMID: 23935503 PMCID: PMC3731240 DOI: 10.1371/journal.ppat.1003528] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Accepted: 06/13/2013] [Indexed: 01/29/2023] Open
Abstract
Neisseria meningitidis is a leading cause of sepsis and meningitis. The bacterium recruits factor H (fH), a negative regulator of the complement system, to its surface via fH binding protein (fHbp), providing a mechanism to avoid complement-mediated killing. fHbp is an important antigen that elicits protective immunity against the meningococcus and has been divided into three different variant groups, V1, V2 and V3, or families A and B. However, immunisation with fHbp V1 does not result in cross-protection against V2 and V3 and vice versa. Furthermore, high affinity binding of fH could impair immune responses against fHbp. Here, we investigate a homologue of fHbp in Neisseria gonorrhoeae, designated as Gonococcal homologue of fHbp (Ghfp) which we show is a promising vaccine candidate for N. meningitidis. We demonstrate that Gfhp is not expressed on the surface of the gonococcus and, despite its high level of identity with fHbp, does not bind fH. Substitution of only two amino acids in Ghfp is sufficient to confer fH binding, while the corresponding residues in V3 fHbp are essential for high affinity fH binding. Furthermore, immune responses against Ghfp recognise V1, V2 and V3 fHbps expressed by a range of clinical isolates, and have serum bactericidal activity against N. meningitidis expressing fHbps from all variant groups. Neisseria meningitidis is a major cause of sepsis and meningitis in young children and adolescents. Although vaccines are currently available against several serogroups, a broadly effective vaccine against serogroup B is still needed. Factor H binding protein (fHbp) can bind the human complement regulator factor H (fH) and is an important meningococcal immunogen. fHbp is divided into three variant groups (V1, V2 and V3) and immunisation with V1 fHbp does not elicit cross-protection against meningococcus expressing fHbp V2 or V3, and vice versa. Here, we investigate a homologue of fHbp in Neisseria gonorrhoeae which we named Gonococcal homologue of factor H binding protein (Ghfp). We show that in contrast to fHbp, Ghfp is not expressed on the bacterial surface and is unable to bind to factor H. Surprisingly, we found that antibodies raised against Ghfp have the capacity to mediate protective immunity against N. meningitidis expressing any of the three variant groups of fHbp, and could provide a broadly protective vaccine against N. meningitidis.
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Pajon R, Fergus AM, Granoff DM. Mutant Native Outer Membrane Vesicles Combined with a Serogroup A Polysaccharide Conjugate Vaccine for Prevention of Meningococcal Epidemics in Africa. PLoS One 2013; 8:e66536. [PMID: 23805230 PMCID: PMC3689835 DOI: 10.1371/journal.pone.0066536] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2013] [Accepted: 05/07/2013] [Indexed: 11/24/2022] Open
Abstract
Background The meningococcal serogroup A (MenA) polysaccharide conjugate vaccine used in Sub-Saharan Africa does not prevent disease caused by MenW or MenX strains, which also cause epidemics in the region. We investigated the vaccine-potential of native outer membrane vesicles with over-expressed factor H-binding protein (NOMV-fHbp), which targeted antigens in African meningococcal strains, and was combined with a MenA polysaccharide conjugate vaccine. Methodology/Principal Findings The NOMV-fHbp vaccine was prepared from a mutant African MenW strain with PorA P1.5,2, attenuated endotoxin (ΔLpxL1), deleted capsular genes, and over-expressed fHbp in variant group 1. The NOMV-fHbp was adsorbed with Al(OH)3 and used to reconstitute a lyophilized MenA conjugate vaccine, which normally is reconstituted with liquid MenC, Y and W conjugates in a meningococcal quadrivalent conjugate vaccine (MCV4-CRM, Novartis). Mice immunized with the NOMV-fHbp vaccine alone developed serum bactericidal (human complement) activity against 13 of 15 African MenA strains tested; 10 of 10 African MenX strains, 7 of 7 African MenW strains, and 6 of 6 genetically diverse MenB strains with fHbp variant group 1 (including 1 strain from The Gambia). The combination NOMV-fHbp/MenA conjugate vaccine elicited high serum bactericidal titers against the two MenA strains tested that were resistant to bactericidal antibodies elicited by the NOMV-fHbp alone; the combination elicited higher titers against the MenA and MenW strains than those elicited by a control MCV4-CRM vaccine (P<0.05); and high titers against MenX and MenB strains. For most strains, the titers elicited by a control NOMV-fHbp knock out vaccine were <1∶10 except when the strain PorA matched the vaccine (titers >1∶000). Conclusion/Significance The NOMV-fHbp/MenA conjugate vaccine provided similar or higher coverage against MenA and MenW strains than a quadrivalent meningococcal conjugate vaccine, and extended protection against MenX strains responsible for epidemics in Africa, and MenB strains with fHbp in variant group 1.
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MESH Headings
- Africa South of the Sahara/epidemiology
- Animals
- Female
- Humans
- Meningitis, Meningococcal/epidemiology
- Meningitis, Meningococcal/genetics
- Meningitis, Meningococcal/immunology
- Meningitis, Meningococcal/prevention & control
- Meningococcal Vaccines/genetics
- Meningococcal Vaccines/immunology
- Mice
- Neisseria meningitidis, Serogroup A/genetics
- Neisseria meningitidis, Serogroup A/immunology
- Polysaccharides, Bacterial/genetics
- Polysaccharides, Bacterial/immunology
- Vaccines, Conjugate/genetics
- Vaccines, Conjugate/immunology
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Affiliation(s)
- Rolando Pajon
- Center for Immunobiology and Vaccine Development, Children’s Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Andrew M. Fergus
- Center for Immunobiology and Vaccine Development, Children’s Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, Children’s Hospital Oakland Research Institute, Oakland, California, United States of America
- * E-mail:
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Konar M, Granoff DM, Beernink PT. Importance of inhibition of binding of complement factor H for serum bactericidal antibody responses to meningococcal factor H-binding protein vaccines. J Infect Dis 2013; 208:627-36. [PMID: 23715659 DOI: 10.1093/infdis/jit239] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
BACKGROUND Factor H (fH) binding protein (fHbp) is part of vaccines developed for prevention of meningococcal serogroup B disease. More than 610 fHbp amino acid sequence variants have been identified, which can be classified into 2 subfamilies. The extent of cross-protection within a subfamily has been difficult to assess because of strain variation in fHbp expression. METHODS Using isogenic mutant strains, we compared cross-protective serum antibody responses of mice immunized with 7 divergent fHbp variants in subfamily B, including identification numbers (ID) 1 and 55, which were chosen for vaccine development. RESULTS AND CONCLUSIONS In the presence of the human complement downregulator fH, the ability of the anti-fHbp antibodies to deposit sufficient complement C3b on the bacterial surface to elicit bactericidal activity required inhibition of binding of fH by the anti-fHbp antibodies. With less bound fH, the bacteria became more susceptible to complement-mediated bactericidal activity. Among the different fHbp sequence variants, those more central in a phylogenic network than ID 1 or 55 elicited anti-fHbp antibodies with broader inhibition of fH binding and broader bactericidal activity. Thus, the more central variants show promise of extending protection to strains with divergent fHbp sequences that are covered poorly by fHbp variants in clinical development.
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Affiliation(s)
- Monica Konar
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, California, USA
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Defining a protective epitope on factor H binding protein, a key meningococcal virulence factor and vaccine antigen. Proc Natl Acad Sci U S A 2013; 110:3304-9. [PMID: 23396847 DOI: 10.1073/pnas.1222845110] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Mapping of epitopes recognized by functional monoclonal antibodies (mAbs) is essential for understanding the nature of immune responses and designing improved vaccines, therapeutics, and diagnostics. In recent years, identification of B-cell epitopes targeted by neutralizing antibodies has facilitated the design of peptide-based vaccines against highly variable pathogens like HIV, respiratory syncytial virus, and Helicobacter pylori; however, none of these products has yet progressed into clinical stages. Linear epitopes identified by conventional mapping techniques only partially reflect the immunogenic properties of the epitope in its natural conformation, thus limiting the success of this approach. To investigate antigen-antibody interactions and assess the potential of the most common epitope mapping techniques, we generated a series of mAbs against factor H binding protein (fHbp), a key virulence factor and vaccine antigen of Neisseria meningitidis. The interaction of fHbp with the bactericidal mAb 12C1 was studied by various epitope mapping methods. Although a 12-residue epitope in the C terminus of fHbp was identified by both Peptide Scanning and Phage Display Library screening, other approaches, such as hydrogen/deuterium exchange mass spectrometry (MS) and X-ray crystallography, showed that mAb 12C1 occupies an area of ∼1,000 Å(2) on fHbp, including >20 fHbp residues distributed on both N- and C-terminal domains. Collectively, these data show that linear epitope mapping techniques provide useful but incomplete descriptions of B-cell epitopes, indicating that increased efforts to fully characterize antigen-antibody interfaces are required to understand and design effective immunogens.
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Dormitzer PR, Grandi G, Rappuoli R. Structural vaccinology starts to deliver. Nat Rev Microbiol 2013; 10:807-13. [PMID: 23154260 DOI: 10.1038/nrmicro2893] [Citation(s) in RCA: 99] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Following the impact of the genomics revolution on vaccine research and the development of reverse vaccinology, it was predicted that another new approach, structure-based antigen design, would become a driving force for vaccine innovation. Now, 5 years on, there are several examples of how structure-based design, or structural vaccinology, can deliver new vaccine antigens that were not possible before. Here, we discuss some of these examples and the contribution of structural vaccinology to our understanding of the protective epitopes of important bacterial and viral pathogens.
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Affiliation(s)
- Philip R Dormitzer
- Novartis Vaccines and Diagnostics Inc., 350 Massachusetts Avenue, Cambridge, Massachusetts 02139, USA
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The new multicomponent vaccine against meningococcal serogroup B, 4CMenB: immunological, functional and structural characterization of the antigens. Vaccine 2012; 30 Suppl 2:B87-97. [PMID: 22607904 DOI: 10.1016/j.vaccine.2012.01.033] [Citation(s) in RCA: 277] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Revised: 01/09/2012] [Accepted: 01/10/2012] [Indexed: 11/22/2022]
Abstract
Neisseria meningitidis is a major cause of endemic cases and epidemics of meningitis and devastating septicemia. Although effective vaccines exist for several serogroups of pathogenic N. meningitidis, conventional vaccinology approaches have failed to provide a universal solution for serogroup B (MenB) which consequently remains an important burden of disease worldwide. The advent of whole-genome sequencing changed the approach to vaccine development, enabling the identification of potential vaccine candidates starting directly with the genomic information, with a process named reverse vaccinology. The application of reverse vaccinology to MenB allowed the identification of new protein antigens able to induce bactericidal antibodies. Three highly immunogenic antigens (fHbp, NadA and NHBA) were combined with outer membrane vesicles and formulated for human use in a multicomponent vaccine, named 4CMenB. This is the first MenB vaccine based on recombinant proteins able to elicit a robust bactericidal immune response in adults, adolescents and infants against a broad range of serogroup B isolates. This review describes the successful story of the development of the 4CMenB vaccine, with particular emphasis on the functional, immunological and structural characterization of the protein antigens included in the vaccine.
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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.
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Beernink PT, Shaughnessy J, Pajon R, Braga EM, Ram S, Granoff DM. The effect of human factor H on immunogenicity of meningococcal native outer membrane vesicle vaccines with over-expressed factor H binding protein. PLoS Pathog 2012; 8:e1002688. [PMID: 22589720 PMCID: PMC3349754 DOI: 10.1371/journal.ppat.1002688] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2012] [Accepted: 03/24/2012] [Indexed: 02/02/2023] Open
Abstract
The binding of human complement inhibitors to vaccine antigens in vivo could diminish their immunogenicity. A meningococcal ligand for the complement down-regulator, factor H (fH), is fH-binding protein (fHbp), which is specific for human fH. Vaccines containing recombinant fHbp or native outer membrane vesicles (NOMV) from mutant strains with over-expressed fHbp are in clinical development. In a previous study in transgenic mice, the presence of human fH impaired the immunogenicity of a recombinant fHbp vaccine. In the present study, we prepared two NOMV vaccines from mutant group B strains with over-expressed wild-type fHbp or an R41S mutant fHbp with no detectable fH binding. In wild-type mice in which mouse fH did not bind to fHbp in either vaccine, the NOMV vaccine with wild-type fHbp elicited 2-fold higher serum IgG anti-fHbp titers (P = 0.001) and 4-fold higher complement-mediated bactericidal titers against a PorA-heterologous strain than the NOMV with the mutant fHbp (P = 0.003). By adsorption, the bactericidal antibodies were shown to be directed at fHbp. In transgenic mice in which human fH bound to the wild-type fHbp but not to the R41S fHbp, the NOMV vaccine with the mutant fHbp elicited 5-fold higher serum IgG anti-fHbp titers (P = 0.002), and 19-fold higher bactericidal titers than the NOMV vaccine with wild-type fHbp (P = 0.001). Thus, in mice that differed only by the presence of human fH, the respective results with the two vaccines were opposite. The enhanced bactericidal activity elicited by the mutant fHbp vaccine in the presence of human fH far outweighed the loss of immunogenicity of the mutant protein in wild-type animals. Engineering fHbp not to bind to its cognate complement inhibitor, therefore, may increase vaccine immunogenicity in humans. Vaccines containing factor H-binding protein (fHbp) are being developed for protection against bacterial meningitis and sepsis caused by meningococci. The antigen was identified from genomic sequences and only later found to bind a human complement protein, factor H (fH), but not fH from non-human species. In previous studies, native outer membrane vesicle (NOMV) vaccines from mutants with over-expressed fHbp elicited broadly protective serum antibodies in mice whose fH did not bind to fHbp in the vaccine. In this study, the authors immunized transgenic mice and showed that the presence of human fH decreased serum bactericidal antibody responses to a NOMV vaccine with fHbp that bound human fH. In contrast, a NOMV vaccine containing fHbp with a single amino acid substitution that eliminated fH binding elicited nearly twenty-fold higher protective antibody responses. Thus, a simple change in a vaccine antigen to eliminate binding to a host protein can increase immunogenicity.
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Affiliation(s)
- Peter T. Beernink
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Jutamas Shaughnessy
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Rolando Pajon
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Emily M. Braga
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Sanjay Ram
- Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, Massachusetts, United States of America
| | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
- * E-mail:
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Hadad R, Jacobsson S, Pizza M, Rappuoli R, Fredlund H, Olcén P, Unemo M. Novel meningococcal 4CMenB vaccine antigens - prevalence and polymorphisms of the encoding genes in Neisseria gonorrhoeae. APMIS 2012; 120:750-60. [PMID: 22882265 DOI: 10.1111/j.1600-0463.2012.02903.x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2011] [Accepted: 03/06/2012] [Indexed: 01/20/2023]
Abstract
The first cross-protective Neisseria meningitidis vaccine (focus on serogroup B), the protein-based 4 component meningococcus serogroup B (4CMenB), includes the New Zealand outer membrane vesicle and three main genome-derived neisserial antigens (GNAs). These GNAs are fHbp (fused to GNA2091), NHBA (fused to GNA1030) and NadA. In this study, the prevalence and polymorphisms of the nucleotide and amino acid sequences of the 4CMenB antigens in a temporally and geographically diverse collection of N. gonorrhoeae isolates (n = 111) were investigated. All the examined GNA genes, except the nadA gene, were present in all gonococcal isolates. However, 25 isolates contained premature stop codons in the fHbp gene and/or the nhba gene, resulting in truncated proteins. Compared with the 4CMenB antigen sequences in reference strain MC58, the gonococcal strains displayed 67.0-95.4% and 60.9-94.9% identity in nucleotide sequence and amino acid sequence, respectively, in the equivalent GNA antigens. The absence of NadA, lack of universal expression of fHbp and NHBA and the uncertainty regarding the surface exposure of fHbp as well as the function of NHBA in N. gonorrhoeae will likely limit the use of the identical 4CMenB antigens in a gonococcal vaccine. However, possible cross-immunity of 4CMenB with gonococci and expression and function of the equivalent gonococcal GNAs, as well as of more appropriate GNAs for a gonococcal vaccine, need to be further examined.
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Affiliation(s)
- Ronza Hadad
- WHO Collaborating Centre for Gonorrhoea and other STIs, National Reference Laboratory for Pathogenic Neisseria, Department of Laboratory Medicine, Clinical Microbiology, Örebro University Hospital, Sweden
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Vu DM, Pajon R, Reason DC, Granoff DM. A broadly cross-reactive monoclonal antibody against an epitope on the n-terminus of meningococcal fHbp. Sci Rep 2012; 2:341. [PMID: 22461972 PMCID: PMC3314305 DOI: 10.1038/srep00341] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2012] [Accepted: 03/05/2012] [Indexed: 11/23/2022] Open
Abstract
Meningococcal factor H binding protein (fHbp) is an important vaccine antigen for prevention of disease caused by capsular group B strains. The protein has been sub-classified into three variant groups. Most anti-fHbp antibodies are variant group-specific and recognize epitopes on the C-terminal domain. We report a murine IgG1 mAb, JAR 41, which broadly cross-reacted with fHbp sequence variants from all variant groups. The mAb bound to the surface of live meningococci with fHbp from each of the three variant groups. In combination with second non-bactericidal anti-fHbp mAbs, JAR 41 elicited complement-mediated bactericidal activity in vitro, and augmented passive protection against meningococcal bacteremia in human fH transgenic rats. The epitope was located on a conserved region of the N-terminal portion of the fHbp molecule opposite that of fH contact residues. The data underscore the importance of broadly cross-reactive, surface-exposed epitopes on the N-terminal domain in the design of protective fHbp vaccines.
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Affiliation(s)
- David M Vu
- Children's Hospital Oakland Research Institute , Oakland, CA 94609, U.S.A
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28
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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.
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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
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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:
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29
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Gorringe AR, Pajón R. Bexsero: a multicomponent vaccine for prevention of meningococcal disease. Hum Vaccin Immunother 2012; 8:174-83. [PMID: 22426368 DOI: 10.4161/hv.18500] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Serogroup B meningococcal (MenB) disease remains a serious public health problem for which a cross-protective vaccine effective against a wide range of MenB isolates has not been available. Novartis Vaccines has developed a vaccine for the prevention of MenB disease that contains four antigenic components: factor H binding protein (fHbp), neisserial adhesin A (NadA), Neisseria heparin binding antigen (NHBA) and outer membrane vesicles from a New Zealand epidemic strain (which provides PorA). This vaccine has been submitted for regulatory review in Europe so it is timely to review the design of the vaccine, results to date in clinical studies and the potential strain coverage provided by the vaccine. It is also critical to discuss the key issues for the long-term success of the vaccine which include strain coverage, potential persistence of protection, potential effects on carriage of MenB strains, potential for escape mutants and cost effectiveness.
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30
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Haghi F, Peerayeh SN, Siadat SD, Zeighami H. Recombinant outer membrane secretin PilQ(406-770) as a vaccine candidate for serogroup B Neisseria meningitidis. Vaccine 2012; 30:1710-4. [PMID: 22234267 DOI: 10.1016/j.vaccine.2011.12.076] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2011] [Revised: 12/01/2011] [Accepted: 12/17/2011] [Indexed: 11/15/2022]
Abstract
Secretin PilQ is an antigenically conserved outer membrane protein which is present on most meningococci. This protein naturally expressed at high levels and is essential for meningococcal pilus expression at the cell surface. A 1095 bp fragment of C-terminal of secretin pilQ from serogroup B Neisseria meningitidis was cloned into prokaryotic expression vector pET-28a. Recombinant protein was overexpressed with IPTG and affinity-purified by Ni-NTA agarose. BALB/c mice were immunized subcutaneously with purified rPilQ(406-770) mixed with Freund's adjuvant. Serum antibody responses to serogroups A and B N. meningitidis whole cells or purified rPilQ(406-770) and functional activity of antibodies were determined by ELISA and SBA, respectively. The output of rPilQ(406-770) was approximately 50% of the total bacterial proteins. Serum IgG responses were significantly increased in immunized group with PilQ(406-770) mixed with Freund's adjuvant in comparison with control groups. Antisera produced against rPilQ(406-770) demonstrated strong surface reactivity to serogroups A and B N. meningitidis tested by whole-cell ELISA. Surface reactivity to serogroup B N. meningitidis was higher than serogroup A. The sera from PilQ(406-770) immunized animals were strongly bactericidal against serogroups A and B. These results suggest that rPilQ(406-770) is a potential vaccine candidate for serogroup B N. meningitidis.
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Affiliation(s)
- Fakhri Haghi
- Department of Bacteriology, Tarbiat Modares University, Tehran, Iran.
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31
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Scarselli M, Aricò B, Brunelli B, Savino S, Di Marcello F, Palumbo E, Veggi D, Ciucchi L, Cartocci E, Bottomley MJ, Malito E, Lo Surdo P, Comanducci M, Giuliani MM, Cantini F, Dragonetti S, Colaprico A, Doro F, Giannetti P, Pallaoro M, Brogioni B, Tontini M, Hilleringmann M, Nardi-Dei V, Banci L, Pizza M, Rappuoli R. Rational design of a meningococcal antigen inducing broad protective immunity. Sci Transl Med 2011; 3:91ra62. [PMID: 21753121 DOI: 10.1126/scitranslmed.3002234] [Citation(s) in RCA: 120] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The sequence variability of protective antigens is a major challenge to the development of vaccines. For Neisseria meningitidis, the bacterial pathogen that causes meningitis, the amino acid sequence of the protective antigen factor H binding protein (fHBP) has more than 300 variations. These sequence differences can be classified into three distinct groups of antigenic variants that do not induce cross-protective immunity. Our goal was to generate a single antigen that would induce immunity against all known sequence variants of N. meningitidis. To achieve this, we rationally designed, expressed, and purified 54 different mutants of fHBP and tested them in mice for the induction of protective immunity. We identified and determined the crystal structure of a lead chimeric antigen that was able to induce high levels of cross-protective antibodies in mice against all variant strains tested. The new fHBP antigen had a conserved backbone that carried an engineered surface containing specificities for all three variant groups. We demonstrate that the structure-based design of multiple immunodominant antigenic surfaces on a single protein scaffold is possible and represents an effective way to create broadly protective vaccines.
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Affiliation(s)
- Maria Scarselli
- Novartis Vaccines and Diagnostics S.r.l., Via Fiorentina 1, 53100 Siena, Italy
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32
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Pajon R, Fergus AM, Koeberling O, Caugant DA, Granoff DM. Meningococcal factor H binding proteins in epidemic strains from Africa: implications for vaccine development. PLoS Negl Trop Dis 2011; 5:e1302. [PMID: 21909444 PMCID: PMC3167780 DOI: 10.1371/journal.pntd.0001302] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2011] [Accepted: 07/21/2011] [Indexed: 01/12/2023] Open
Abstract
BACKGROUND Factor H binding protein (fHbp) is an important antigen for vaccines against meningococcal serogroup B disease. The protein binds human factor H (fH), which enables the bacteria to resist serum bactericidal activity. Little is known about the vaccine-potential of fHbp for control of meningococcal epidemics in Africa, which typically are caused by non-group B strains. METHODOLOGY/PRINCIPAL FINDINGS We investigated genes encoding fHbp in 106 serogroup A, W-135 and X case isolates from 17 African countries. We determined complement-mediated bactericidal activity of antisera from mice immunized with recombinant fHbp vaccines, or a prototype native outer membrane vesicle (NOMV) vaccine from a serogroup B mutant strain with over-expressed fHbp. Eighty-six of the isolates (81%) had one of four prevalent fHbp sequence variants, ID 4/5 (serogroup A isolates), 9 (W-135), or 74 (X) in variant group 1, or ID 22/23 (W-135) in variant group 2. More than one-third of serogroup A isolates and two-thirds of W-135 isolates tested had low fHbp expression while all X isolates tested had intermediate or high expression. Antisera to the recombinant fHbp vaccines were generally bactericidal only against isolates with fHbp sequence variants that closely matched the respective vaccine ID. Low fHbp expression also contributed to resistance to anti-fHbp bactericidal activity. In contrast to the recombinant vaccines, the NOMV fHbp ID 1 vaccine elicited broad anti-fHbp bactericidal activity, and the antibodies had greater ability to inhibit binding of fH to fHbp than antibodies elicited by the control recombinant fHbp ID 1 vaccine. CONCLUSION/SIGNIFICANCE NOMV vaccines from mutants with increased fHbp expression elicit an antibody repertoire with greater bactericidal activity than recombinant fHbp vaccines. NOMV vaccines are promising for prevention of meningococcal disease in Africa and could be used to supplement coverage conferred by a serogroup A polysaccharide-protein conjugate vaccine recently introduced in some sub-Saharan countries.
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Affiliation(s)
- Rolando Pajon
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Andrew M. Fergus
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Oliver Koeberling
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
| | - Dominique A. Caugant
- Department of Bacteriology and Immunology, Norwegian Institute of Public Health, and Department of Community Medicine, University of Oslo, Oslo, Norway
| | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, United States of America
- * E-mail:
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33
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Koeberling O, Seubert A, Santos G, Colaprico A, Ugozzoli M, Donnelly J, Granoff DM. Immunogenicity of a meningococcal native outer membrane vesicle vaccine with attenuated endotoxin and over-expressed factor H binding protein in infant rhesus monkeys. Vaccine 2011; 29:4728-34. [PMID: 21571025 PMCID: PMC3114263 DOI: 10.1016/j.vaccine.2011.04.095] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2011] [Revised: 04/13/2011] [Accepted: 04/25/2011] [Indexed: 11/23/2022]
Abstract
We previously investigated immunogenicity of meningococcal native outer membrane vesicle (NOMV) vaccines prepared from recombinant strains with attenuated endotoxin (ΔLpxL1) and over-expressed factor H binding protein (fHbp) in a mouse model. The vaccines elicited broad serum bactericidal antibody responses. While human toll-like receptor 4 (TLR-4) is mainly stimulated by wildtype meningococcal endotoxin, mouse TLR-4 is stimulated by both the wildtype and mutant endotoxin. An adjuvant effect in mice of the mutant endotoxin would be expected to be much less in humans, and may have contributed to the broad mouse bactericidal responses. Here we show that as previously reported for humans, rhesus primate peripheral blood mononuclear cells incubated with a NOMV vaccine from ΔLpxL1 recombinant strains had lower proinflammatory cytokine responses than with a control wildtype NOMV vaccine. The cytokine responses to the mutant vaccine were similar to those elicited by a detergent-treated, wildtype outer membrane vesicle vaccine that had been safely administered to humans. Monkeys (N=4) were immunized beginning at ages 2-3 months with three doses of a NOMV vaccine prepared from ΔLpxL1 recombinant strains with over-expressed fHbp in the variant 1 and 2 groups. The mutant NOMV vaccine elicited serum bactericidal titers≥1:4 against all 10 genetically diverse strains tested, including 9 with heterologous PorA to those in the vaccine. Negative-control animals had serum bactericidal titers<1:4. Thus, the mutant NOMV vaccine elicited broadly protective serum antibodies in a non-human infant primate model that is more relevant for predicting human antibody responses than mice.
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Affiliation(s)
| | | | | | | | | | | | - Dan M. Granoff
- Center for Immunobiology and Vaccine Development, Children’s Hospital Oakland Research Institute, Oakland, CA 94609
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34
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Zhu W, Chen CJ, Thomas CE, Anderson JE, Jerse AE, Sparling PF. Vaccines for gonorrhea: can we rise to the challenge? Front Microbiol 2011; 2:124. [PMID: 21687431 PMCID: PMC3109613 DOI: 10.3389/fmicb.2011.00124] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2011] [Accepted: 05/19/2011] [Indexed: 12/14/2022] Open
Abstract
Immune responses to the gonococcus after natural infection ordinarily result in little immunity to reinfection, due to antigenic variation of the gonococcus, and redirection or suppression of immune responses. Brinton and colleagues demonstrated that parenteral immunization of male human volunteers with a purified pilus vaccine gave partial protection against infection by the homologous strain. However, the vaccine failed in a clinical trial. Recent vaccine development efforts have focused on the female mouse model of genital gonococcal infection. Here we discuss the state of the field, including our unpublished data regarding efficacy in the mouse model of either viral replicon particle (VRP) vaccines, or outer membrane vesicle (OMV) vaccines. The OMV vaccines failed, despite excellent serum and mucosal antibody responses. Protection after a regimen consisting of a PorB-VRP prime plus recombinant PorB boost was correlated with apparent Th1, but not with antibody, responses. Protection probably was due to powerful adjuvant effects of the VRP vector. New tools including novel transgenic mice expressing human genes required for gonococcal infection should enable future research. Surrogates for immunity are needed. Increasing antimicrobial resistance trends among gonococci makes development of a vaccine more urgent.
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Affiliation(s)
- Weiyan Zhu
- Department of Medicine, University of North Carolina Chapel Hill, NC, USA
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35
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Beernink PT, Shaughnessy J, Braga EM, Liu Q, Rice PA, Ram S, Granoff DM. A meningococcal factor H binding protein mutant that eliminates factor H binding enhances protective antibody responses to vaccination. THE JOURNAL OF IMMUNOLOGY 2011; 186:3606-14. [PMID: 21325619 DOI: 10.4049/jimmunol.1003470] [Citation(s) in RCA: 117] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Certain pathogens recruit host complement inhibitors such as factor H (fH) to evade the immune system. Microbial complement inhibitor-binding molecules can be promising vaccine targets by eliciting Abs that neutralize this microbial defense mechanism. One such Ag, meningococcal factor H-binding protein (fHbp), was used in clinical trials before the protein was discovered to bind fH. The potential effect of fH binding on vaccine immunogenicity had not been assessed in experimental animals because fHbp binds human fH specifically. In this study, we developed a human fH transgenic mouse model. Transgenic mice immunized with fHbp vaccine had 4- to 8-fold lower serum bactericidal Ab responses than those of control mice whose native fH did not bind the vaccine. In contrast, Ab responses were unimpaired in transgenic mice immunized with a control meningococcal group C polysaccharide-protein conjugate vaccine. In transgenic mice, immunization with an fH nonbinding mutant of fHbp elicited Abs with higher bactericidal activity than that of fHbp vaccination itself. Abs elicited by the mutant fHbp more effectively blocked fH binding to wild-type fHbp than Abs elicited by fHbp that bound fH. Thus, a mutant fHbp vaccine that does not bind fH but that retains immunogenicity is predicted to be superior in humans to an fHbp vaccine that binds human fH. In the case of mutant fHbp vaccination, the resultant Ab responses may be directed more at epitopes in or near the fH binding site, which result in greater complement-mediated serum bactericidal activity; these epitopes may be obscured when human fH is bound to the wild-type fHbp vaccine.
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Affiliation(s)
- Peter T Beernink
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
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36
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Vu DM, Wong TT, Granoff DM. Cooperative serum bactericidal activity between human antibodies to meningococcal factor H binding protein and neisserial heparin binding antigen. Vaccine 2011; 29:1968-73. [PMID: 21241734 DOI: 10.1016/j.vaccine.2010.12.075] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/10/2010] [Accepted: 12/16/2010] [Indexed: 11/20/2022]
Abstract
A meningococcal group B vaccine containing multiple protein antigens including factor H binding protein (fHbp) and Neisserial heparin binding antigen (NHba) is in clinical development. The ability of antibodies against individual antigens to interact and augment protective immunity is unknown. We assayed human complement-mediated bactericidal activity (SBA) in stored sera from six immunized adults before and after depletion of antibodies to fHbp and/or NHba. All six subjects developed ≥ 4-fold increases in SBA titer against a test strain with fHbp in the variant 1 group with an amino acid sequence that matched the vaccine antigen (GMT <1:4 baseline, to 1:139 after 3 doses of vaccine). By adsorption 88 to >95% of the SBA was directed against fHbp. Four subjects developed ≥ 4-fold increases in SBA titer against a test strain with a heterologous fHbp variant 2 antigen and a homologous NHba amino acid sequence that matched the vaccine antigen (GMT <1:4 baseline, to 1:45). SBA was directed primarily against NHba in one subject, against fHbp in a second, while depletion of either anti-NHba or anti-fHbp antibody removed the majority of SBA in sera from two subjects. In all four subjects, depletion of both anti-fHbp and anti-NHba antibodies removed more SBA than depletion of either antibody individually. Mixing a mouse non-bactericidal anti-fHbp variant 1 antiserum with a mouse anti-NHba antiserum also augmented the anti-NHba SBA titer against this test strain. For meningococcal vaccines that target relatively sparsely exposed antigens such fHbp or NHba, non-bactericidal antibodies against individual antigens can cooperate and elicit SBA.
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Affiliation(s)
- David M Vu
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, USA
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Effect of factor H-binding protein sequence variation on factor H binding and survival of Neisseria meningitidis in human blood. Infect Immun 2010; 79:353-9. [PMID: 21041484 DOI: 10.1128/iai.00849-10] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Binding of the complement inhibitor factor H (fH) to the surface of Neisseria meningitidis is critical for evasion of innate host defenses. The meningococcal vaccine candidate factor H-binding protein (fHbp) serves as an fH ligand. We prepared 16 recombinant fHbp natural sequence variants. By enzyme-linked immunosorbent assay (ELISA), the variants from a New Zealand epidemic strain (fHbp ID 14) and from an endemic United Kingdom strain (ID 15) showed 10-fold lower fH binding than a reference fHbp from an epidemic Norwegian strain (ID 1). By surface plasmon resonance, association rate constants (k(a)) for fHbp ID 14 and 15 were similar to those for ID 1, but dissociation rate constants (k(d)) were 4- to 10-fold higher than those for ID 1. To determine the effect of fH affinity on fHbp fitness, we prepared isogenic mutants of strain H44/76 that expressed fHbp ID 1, 14, or 15. By flow cytometry, mutants expressing fHbp ID 14 or 15 had lower fH binding than ID 1. When incubated in plasma or blood of nonimmune donors, all three mutants showed similar increases in CFU/ml. In contrast, an isogenic fHbp knockout mutant, which grew well in broth, was rapidly killed in plasma or blood. Thus, although fHbp expression was required for survival of strain H44/76 in blood or plasma, expression of two natural fHbp sequence variants with lower fH affinity had minimal or no effect on nonimmune clearance. One reason may be the high fH concentrations in normal serum, which favor saturation of fH binding to fHbp, even when dissociation rates varied over 10-fold.
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Qualitative and quantitative assessment of meningococcal antigens to evaluate the potential strain coverage of protein-based vaccines. Proc Natl Acad Sci U S A 2010; 107:19490-5. [PMID: 20962280 DOI: 10.1073/pnas.1013758107] [Citation(s) in RCA: 245] [Impact Index Per Article: 17.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A unique multicomponent vaccine against serogroup B meningococci incorporates the novel genome-derived proteins fHbp, NHBA, and NadA that may vary in sequence and level of expression. Measuring the effectiveness of such vaccines, using the accepted correlate of protection against invasive meningococcal disease, could require performing the serum bactericidal assay (SBA) against many diverse strains for each geographic region. This approach is impractical, especially for infants, where serum volumes are very limited. To address this, we developed the meningococcal antigen typing system (MATS) by combining a unique vaccine antigen-specific ELISA, which detects qualitative and quantitative differences in antigens, with PorA genotyping information. The ELISA correlates with killing of strains by SBA and measures both immunologic cross-reactivity and quantity of the antigens NHBA, NadA, and fHbp. We found that strains exceeding a threshold value in the ELISA for any of the three vaccine antigens had ≥80% probability of being killed by immune serum in the SBA. Strains positive for two or more antigens had a 96% probability of being killed. Inclusion of multiple different antigens in the vaccine improves breadth of coverage and prevents loss of coverage if one antigen mutates or is lost. The finding that a simple and high-throughput assay correlates with bactericidal activity is a milestone in meningococcal vaccine development. This assay allows typing of large panels of strains and prediction of coverage of protein-based meningococcal vaccines. Similar assays may be used for protein-based vaccines against other bacteria.
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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.
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40
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Impaired immunogenicity of a meningococcal factor H-binding protein vaccine engineered to eliminate factor h binding. CLINICAL AND VACCINE IMMUNOLOGY : CVI 2010; 17:1074-8. [PMID: 20519444 DOI: 10.1128/cvi.00103-10] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Meningococcal factor H-binding protein (fHbp) is a promising antigen that is part of two vaccines in clinical development. The protein specifically binds human complement factor H (fH), which downregulates complement activation on the bacterial surface and enables the organism to evade host defenses. In humans, the vaccine antigen forms a complex with fH, which may affect anti-fHbp antibody repertoire and decrease serum bactericidal activity by covering important fHbp epitopes. In a recent study, fHbp residues in contact with fH were identified from a crystal structure. Two fHbp glutamate residues that mediated ion-pair interactions with fH were replaced with alanine, and the resulting E218A/E239A mutant no longer bound the fH fragment. In the present study, we generated the E218A/E239A mutant recombinant protein and confirmed the lack of fH binding. By enzyme-linked immunosorbent assay (ELISA), the mutant fHbp showed similar respective concentration-dependent inhibition of binding of four bactericidal anti-fHbp monoclonal antibodies (MAbs) to fHbp, compared with inhibition by the soluble wild-type protein. In two mouse strains, the mutant fHbp elicited up to 4-fold-lower IgG anti-fHbp antibody titers and up to 20-fold-lower serum bactericidal titers than those elicited by the wild-type fHbp vaccine. Thus, although introduction of the two alanine substitutions to eliminate fH binding did not appear to destabilize the molecule globally, the mutations resulted in decreased immunogenicity in mouse models in which neither the mutant nor the wild-type control vaccine bound fH. These results cast doubt on the vaccine potential in humans of this mutant fHbp.
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Giuliani MM, Biolchi A, Serruto D, Ferlicca F, Vienken K, Oster P, Rappuoli R, Pizza M, Donnelly J. Measuring antigen-specific bactericidal responses to a multicomponent vaccine against serogroup B meningococcus. Vaccine 2010; 28:5023-30. [PMID: 20493284 DOI: 10.1016/j.vaccine.2010.05.014] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2009] [Revised: 05/03/2010] [Accepted: 05/05/2010] [Indexed: 10/19/2022]
Abstract
Serum bactericidal activity using human complement is the basis for established correlates of protection against invasive meningococcal disease. During the development of multicomponent protein-based vaccines against meningococcus B, it is necessary to measure antigen-specific bactericidal responses. This is not straightforward because each strain may be killed by antibodies to multiple antigens. We characterized a large panel of strains and, using a competitive inhibition SBA, we identified four strains that are each specifically killed by bactericidal antibodies to one of the major vaccine components. These strains provide a straightforward approach to demonstrate protective responses to each component of the vaccine and demonstrate that each of the antigens in the vaccine is sufficient to provide a potentially protective level of bactericidal activity.
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Affiliation(s)
- Marzia M Giuliani
- Novartis Vaccines and Diagnostics, Via Fiorentina 1, Siena 53100, Italy
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Abstract
No broadly effective vaccines are available for prevention of group B meningococcal disease, which accounts for >50% of all cases. The group B capsule is an autoantigen and is not a suitable vaccine target. Outer-membrane vesicle vaccines appear to be safe and effective, but serum bactericidal responses in infants are specific for a porin protein, PorA, which is antigenically variable. To broaden protection, outer-membrane vesicle vaccines have been prepared from >1 strain, from mutants with >1 PorA, or from mutants with genetically detoxified endotoxin and overexpressed desirable antigens, such as factor H binding protein. Also, recombinant protein vaccines such as factor H binding protein, given alone or in combination with other antigens, are in late-stage clinical development and may be effective against the majority of group B strains. Thus, the prospects have never been better for developing vaccines for prevention of meningococcal disease, including that caused by group B strains.
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Affiliation(s)
- Dan M Granoff
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, California, USA.
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Affiliation(s)
- Lionel K K Tan
- Centre for Molecular Microbiology and Infection, Imperial College London, London, United Kingdom
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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]
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Frequency of factor H-binding protein modular groups and susceptibility to cross-reactive bactericidal activity in invasive meningococcal isolates. Vaccine 2009; 28:2122-9. [PMID: 20044056 DOI: 10.1016/j.vaccine.2009.12.027] [Citation(s) in RCA: 76] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2009] [Revised: 12/03/2009] [Accepted: 12/14/2009] [Indexed: 11/22/2022]
Abstract
Meningococcal factor H-binding protein (fHbp) is a promising vaccine candidate that elicits serum bactericidal antibodies in humans. Based on sequence variability of the entire protein, fHbp has been divided into three variant groups or two sub-families. We recently reported that the fHbp architecture was modular, consisting of five variable segments, each encoded by genes from one of two lineages. Based on combinations of segments from different lineages, all 70 known fHbp sequence variants could be classified into one of six modular groups. In this study, we analyzed sequences of 172 new fHbp variants that were available from public databases. All but three variants could be classified into one of the six previously described modular groups. Among systematically collected invasive group B isolates from the U.S. and Europe, modular group I overall was most common (60%) but group IV (natural chimeras) accounted for 23% of UK isolates and <1% of U.S. isolates (P<0.0001). Mouse antisera to recombinant fHbp from each of the modular groups showed modular group-specific bactericidal activity against strains with low fHbp expression but had broader activity against strains with higher fHbp expression. Thus both modular group and relative expression of fHbp affected strain susceptibility to anti-fHbp bactericidal activity. The results confirmed the modular architecture of fHbp and underscored its importance for the design of broadly protective group B vaccines in different regions.
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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.
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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
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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
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Expression of factor H binding protein of meningococcus responds to oxygen limitation through a dedicated FNR-regulated promoter. J Bacteriol 2009; 192:691-701. [PMID: 19948796 DOI: 10.1128/jb.01308-09] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [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 surface-exposed lipoprotein in Neisseria meningitidis, which is a component of several investigational vaccines against serogroup B meningococcus (MenB) currently in development. fHBP enables the bacterium to evade complement-mediated killing by binding factor H, a key downregulator of the complement alternative pathway, and, in addition, fHBP is important for meningococcal survival in the presence of the antimicrobial peptide LL-37. In this study, we investigate the molecular mechanisms involved in transcription and regulation of the fHBP-encoding gene, fhbp. We show that the fHBP protein is expressed from two independent transcripts: one bicistronic transcript that includes the upstream gene and a second shorter monocistronic transcript from its own dedicated promoter, P(fhbp). Transcription from the promoter P(fhbp) responds to oxygen limitation in an FNR-dependent manner, and, accordingly, the FNR protein binds to a P(fhbp) probe in vitro. Furthermore, expression in meningococci of a constitutively active FNR mutant results in the overexpression of the fHBP protein. Finally, the analysis of fHBP regulation was extended to a panel of strains expressing different fHBP allelic variants at different levels, and we demonstrate that FNR is involved in the regulation of this antigen in all but one of the strains tested. Our data suggest that oxygen limitation may play an important role in inducing the expression of fHBP from a dedicated FNR-regulated promoter. This implies a role for this protein in microenvironments lacking oxygen, for instance in the submucosa or intracellularly, in addition to its demonstrated role in serum resistance in the blood.
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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.
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Beernink PT, Granoff DM. The modular architecture of meningococcal factor H-binding protein. MICROBIOLOGY-SGM 2009; 155:2873-2883. [PMID: 19574307 DOI: 10.1099/mic.0.029876-0] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Meningococcal factor H binding protein (fHbp) is a promising vaccine antigen that binds the human complement downregulatory molecule factor H (fH), and this binding enhances the survival of the organism in serum. Based on sequence variability of the entire protein, fHbp has been divided into three variant groups or two subfamilies. Here, we present evidence based on phylogenetic analysis of 70 unique fHbp amino acid sequences that the molecular architecture is modular. From sequences of natural chimeras we identified blocks of two to five invariant residues that flanked five modular variable segments. Although overall, 46 % of the fHbp amino acids were invariant, based on a crystal structure, the invariant blocks that flanked the modular variable segments clustered on the membrane surface containing the amino-terminal lipid anchor, while the remaining invariant residues were located throughout the protein. Each of the five modular variable segments could be classified into one of two types, designated alpha or beta, based on homology with segments encoded by variant 1 or 3 fHbp genes, respectively. Forty of the fHbps (57 %) comprised only alpha (n=33) or beta (n=7) type segments. The remaining 30 proteins (43 %) were chimeras and could be classified into one of four modular groups. These included all 15 proteins assigned to the previously described variant 2 in subfamily A. The modular segments of one chimeric modular group had 96 % amino acid identity with those of fHbp orthologs in Neisseria gonorrhoeae. Collectively, the data suggest that recombination between Neisseria meningitidis and N. gonorrhoeae progenitors generated a family of modular, antigenically diverse meningococcal fHbps.
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Affiliation(s)
- Peter T Beernink
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
| | - Dan M Granoff
- Center for Immunobiology and Vaccine Development, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA
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