A Broadly Cross-Reactive Monoclonal Antibody Against an Epitope on the N-terminus of Meningococcal fHbp

Vu, David M.; Pajón, Rolando; Reason, Donald C.; Granoff, Dan M.

doi:10.1038/srep00341

Cited by 38 publications

(46 citation statements)

References 43 publications

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“…Each fHbp amino acid sequence variant is assigned a unique identification (ID) number ("peptide ID") such as ID 1 or ID 352. Based on analysis of amino acid sequence similarity, fHbp variants have been subdivided into two subfamilies (A and B) (21,41), three variant groups (v.1, v.2, and v.3) (38), or 10 modular groups (I through X) (53). Modular groups I to VI accounted for nearly all disease-causing isolates (4,42).…”

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confidence: 99%

Design of Meningococcal Factor H Binding Protein Mutant Vaccines That Do Not Bind Human Complement Factor H

Pajón¹,

Beernink²,

Granoff³

2012

Infect Immun

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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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confidence: 99%

Design of Meningococcal Factor H Binding Protein Mutant Vaccines That Do Not Bind Human Complement Factor H

Pajón¹,

Beernink²,

Granoff³

2012

Infect Immun

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“…Several previous epitope mapping studies have been performed on fHbp using NMR spectroscopy (14,15), scanning of synthetic peptide arrays (16), and phage-or yeast-display techniques (17)(18)(19). The interpretation of these studies was facilitated by the 3D structures of fHbp alone (20,21) or in complex with hfH (22).…”

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Defining a protective epitope on factor H binding protein, a key meningococcal virulence factor and vaccine antigen

Malito

Faleri

Surdo

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

126

166

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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.meningococcus | structure | surface plasmon resonance | structural mass spectrometry | antigen-antibody complex

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“…It is an immune system-evading protein protecting the meningococci from complement-mediated lysis by binding the human complement-inhibiting protein factor H (FH) (13). Antibodies to FHbp elicit SBA and confer passive protection in infant rat meningococcal bacteremia models (14,15). PorA is estimated to make up 25% of the outer membrane of meningococci, while FHbp is estimated to make up 1% (16).…”

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Human IgG1, IgG3, and IgG3 Hinge-Truncated Mutants Show Different Protection Capabilities against Meningococci Depending on the Target Antigen and Epitope Specificity

Giuntini

Granoff

Beernink

et al. 2016

Clin Vaccine Immunol

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We compared the bactericidal activity of recombinant sets of chimeric IgG monoclonal antibodies against two important outer membrane meningococcal vaccine antigens: PorA and factor H binding protein (FHbp). The sets contained human Fc portions from IgG1, IgG3, and two IgG3 mutants (IgG3m15 and IgGm17) with hinge regions of 15 and 17 amino acids encoded by hinge exons h2 and h1, respectively (human IgG3 has a hinge region of 62 amino acids encoded by hinge exons h1, h2, h3, and h4, while human IgG1 has a hinge region of only 15 amino acids encoded by one hinge exon) and mouse V regions. IgG1 showed higher bactericidal activity than IgG3 when directed against PorA (an abundant antigen), while IgG3 was more bactericidal than IgG1 when directed against FHbp (a sparsely and variably distributed antigen). On the other hand, the IgG3 hinge-truncated antibodies IgG3m15 and IgGm17 showed higher bactericidal activity than both IgG1 and IgG3 regardless of the target antigen. Thus, the Fc region of IgG3 antibodies appears to have an enhanced complement-activating function, independent of their long hinge region, compared to IgG1 antibodies. The greater activity of the truncated IgG3 hinge mutants indicates that the long hinge of IgG3 seems to downregulate through an unknown mechanism the inherent increased complement-activating capability of IgG3 Fc when the antibody binds to a sparse antigen. Immune protection against invasive meningococcal disease depends on recognition of bacterial surface antigens by antibodies, followed by activation of complement, leading to degradation of the bacteria by bacteriolysis, also named serum bactericidal activity (SBA). The class 1 outer membrane porin protein PorA is abundantly expressed by almost all meningococcal strains (1-3), and antigenic variation among PorA proteins is the basis of serosubtyping (1). PorA can induce bactericidal antibodies in humans and mice when they are immunized with meningococcal outer membrane vesicle (OMV) vaccines (4-8), and monoclonal antibodies (MAbs) against PorA can be protective in an infant rat model (9). Factor H binding protein (FHbp) is a lipoprotein that is sparsely distributed on the outer membrane of many meningococcal strains (10-12). It is an immune system-evading protein protecting the meningococci from complement-mediated lysis by binding the human complement-inhibiting protein factor H (FH) (13). Antibodies to FHbp elicit SBA and confer passive protection in infant rat meningococcal bacteremia models (14, 15). PorA is estimated to make up 25% of the outer membrane of meningococci, while FHbp is estimated to make up 1% (16).Human IgG consists of four subclasses (isotypes), IgG1, IgG2, IgG3, and IgG4, which differ greatly in effector functions, such as interaction with FcR on immune cells and the capacity to activate complement (17-19). By using monoclonal hapten (4-hydroxy-3-nitrophenacetyl [NP/NIP])-specific antibodies of all four IgG isotypes, we have demonstrated that IgG1 and IgG3 are best in inducing complement-mediated cellular lysis an...

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A Broadly Cross-Reactive Monoclonal Antibody Against an Epitope on the N-terminus of Meningococcal fHbp

Cited by 38 publications

References 43 publications

Design of Meningococcal Factor H Binding Protein Mutant Vaccines That Do Not Bind Human Complement Factor H

Design of Meningococcal Factor H Binding Protein Mutant Vaccines That Do Not Bind Human Complement Factor H

Defining a protective epitope on factor H binding protein, a key meningococcal virulence factor and vaccine antigen

Human IgG1, IgG3, and IgG3 Hinge-Truncated Mutants Show Different Protection Capabilities against Meningococci Depending on the Target Antigen and Epitope Specificity

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