scholarly journals Bactericidal Antibody Responses Induced by Meningococcal Recombinant Chimeric Factor H-Binding Protein Vaccines

2008 ◽  
Vol 76 (6) ◽  
pp. 2568-2575 ◽  
Author(s):  
Peter T. Beernink ◽  
Dan M. Granoff
Keyword(s):  
Bactericidal Activity ◽  
Vaccine Candidate ◽  
Binding Protein ◽  
Regulatory Protein ◽  
Factor H ◽  
Enzyme Linked Immunosorbent Assay ◽  
Meningococcal Vaccine ◽  
Serum Antibodies ◽  
Classical Complement Pathway ◽  
Protein Factor

ABSTRACT Factor H-binding protein (fHbp) is a novel meningococcal vaccine candidate that elicits serum antibodies that activate classical complement pathway bacteriolysis and also inhibit binding of the complement down-regulatory protein, factor H, to the bacterial surface. One limitation of fHbp as a vaccine candidate is antigenic variability, since antibodies to fHbp in the variant 1 (v.1) antigenic group do not protect against strains expressing v.2 or v.3 proteins, and vice versa. We have identified amino acid residues of epitopes recognized by bactericidal anti-fHbp monoclonal antibodies prepared against fHbp from each of the variant groups. One epitope expressed by nearly all v.1 proteins mapped to the B domain, while epitopes expressed by fHbp v.2 or v.3 mapped to the C domain. The results provided the rationale for engineering chimeric fHbp molecules containing the A domain (which is conserved across all variant groups), a portion of the B domain of a v.1 protein, and the carboxyl-terminal portion of the B domain and the C domain of a v.2 protein. By enzyme-linked immunosorbent assay, the resulting recombinant chimeric proteins expressed epitopes from all three variant groups. In mice, the chimeric vaccines elicited serum antibodies with bactericidal activity against a panel of genetically diverse strains expressing fHbp v.1, v.2, or v.3. The data demonstrate the feasibility of preparing a meningococcal vaccine from a single recombinant protein that elicits broad bactericidal activity, including group B strains, which account for 50 percent of cases of meningococcal disease and for which there currently is no broadly protective vaccine.

scholarly journals The Meningococcal Vaccine Candidate GNA1870 Binds the Complement Regulatory Protein Factor H and Enhances Serum Resistance

2006 ◽  
Vol 177 (1) ◽  
pp. 501-510 ◽  
Author(s):  
Guillermo Madico ◽  
Jo Anne Welsch ◽  
Lisa A. Lewis ◽  
Anne McNaughton ◽  
David H. Perlman ◽  
...  
Keyword(s):  
Vaccine Candidate ◽  
Regulatory Protein ◽  
Factor H ◽  
Serum Resistance ◽  
Meningococcal Vaccine ◽  
Complement Regulatory Protein ◽  
Protein Factor

scholarly journals Complement-Mediated Bactericidal Activity of Anti-Factor H Binding Protein Monoclonal Antibodies against the Meningococcus Relies upon Blocking Factor H Binding

2011 ◽  
Vol 79 (9) ◽  
pp. 3751-3759 ◽  
Author(s):  
Serena Giuntini ◽  
Donald C. Reason ◽  
Dan M. Granoff
Keyword(s):  
Monoclonal Antibodies ◽  
Bactericidal Activity ◽  
Specific Binding ◽  
Binding Protein ◽  
High Serum ◽  
Factor H ◽  
High Avidity ◽  
Human Complement ◽  
Classical Complement Pathway ◽  
Protein Factor

ABSTRACTBinding of the complement-downregulating protein factor H (fH) to the surface of the meningococcus is important for survival of the organism in human serum. The meningococcal vaccine candidate factor H binding protein (fHbp) is an important ligand for human fH. While some fHbp-specific monoclonal antibodies (MAbs) block binding of fH to fHbp, the stoichiometry of blocking in the presence of high serum concentrations of fH and its effect on complement-mediated bactericidal activity are unknown. To investigate this question, we constructed chimeric antibodies in which the human IgG1 constant region was paired with three murine fHbp-specific binding domains designated JAR 3, JAR 5, and MAb502. By surface plasmon resonance, the association rates for binding of all three MAbs to immobilized fHbp were >50-fold higher than that for binding of fH to fHbp, and the MAb dissociation rates were >500-fold lower than that for fH. While all three MAbs elicited similar C1q-dependent C4b deposition on live bacteria (classical complement pathway), only those antibodies that inhibited binding of fH to fHbp (JAR 3 and JAR 5) had bactericidal activity with human complement. MAb502, which did not inhibit fH binding, had complement-mediated bactericidal activity only when tested with fH-depleted human complement. When an IgG1 anti-fHbp MAb binds to sparsely exposed fHbp on the bacterial surface, there appears to be insufficient complement activation for bacteriolysis unless fH binding also is inhibited. The ability of fHbp vaccines to elicit protective antibodies, therefore, is likely to be enhanced if the antibody repertoire is of high avidity and includes fH-blocking activity.

scholarly journals M Protein of the Group A StreptococcusBinds to the Seventh Short Consensus Repeat of Human Complement Factor H

1998 ◽  
Vol 66 (4) ◽  
pp. 1427-1431 ◽  
Author(s):  
Timothy K. Blackmore ◽  
Vincent A. Fischetti ◽  
Tania A. Sadlon ◽  
Helena M. Ward ◽  
David L. Gordon
Keyword(s):  
Protein Binding ◽  
Binding Site ◽  
Regulatory Protein ◽  
Factor H ◽  
M Protein ◽  
Protein Binding Site ◽  
Enzyme Linked Immunosorbent Assay ◽  
Complement Factor ◽  
Heparin Binding ◽  
Protein Factor

ABSTRACT Streptococcus pyogenes evades complement by binding the complement-regulatory protein factor H (fH) via the central conserved C-repeat region of M protein. However, the corresponding binding region within fH has not previously been precisely localized. fH is composed of 20 conserved modules called short consensus repeats (SCRs), each of which contains approximately 60 amino acids. A series of fH truncated and deletion mutants were prepared, and their interaction with M6 protein was examined. The M protein binding site was initially localized to SCRs 6 to 15 as demonstrated by ligand dot blotting, chemical cross-linking, and enzyme-linked immunosorbent assay. SCR 7 was then shown to contain the M protein binding site, as a construct consisting of the first seven SCRs bound M protein but a construct containing the first six SCRs did not bind. In addition, deletion of SCR 7 from full-length fH abolished binding to M protein. SCR 7 is known to contain a heparin binding domain, and binding of fH to M6 protein was almost totally inhibited in the presence of 400 U of heparin per ml. These results localize the M6 protein binding site of fH to SCR 7 and indicate that it is in close proximity to the heparin binding site.

scholarly journals Fine Antigenic Specificity and Cooperative Bactericidal Activity of Monoclonal Antibodies Directed at the Meningococcal Vaccine Candidate Factor H-Binding Protein

2008 ◽  
Vol 76 (9) ◽  
pp. 4232-4240 ◽  
Author(s):  
Peter T. Beernink ◽  
Jo Anne Welsch ◽  
Michal Bar-Lev ◽  
Oliver Koeberling ◽  
Maurizio Comanducci ◽  
...  
Keyword(s):  
Amino Acids ◽  
Monoclonal Antibodies ◽  
Bactericidal Activity ◽  
Binding Protein ◽  
Factor H ◽  
Antigenic Specificity ◽  
Complement Protein ◽  
Antigenic Variant ◽  
Classical Complement Pathway ◽  
Group B

ABSTRACT No broadly protective vaccine is available for the prevention of group B meningococcal disease. One promising candidate is factor H-binding protein (fHbp), which is present in all strains but often sparsely expressed. We prepared seven murine immunoglobulin G monoclonal antibodies (MAbs) against fHbp from antigenic variant group 2 (v.2) or v.3 (∼40% of group B strains). Although none of the MAbs individually elicited bactericidal activity with human complement, all had activity in different combinations. We used MAb reactivity with strains expressing fHbp polymorphisms and site-specific mutagenesis to identify residues that are important for epitopes recognized by six of the v.2 or v.3 MAbs and by two v.1 MAbs that were previously characterized. Residues affecting v.2 or v.3 epitopes resided between amino acids 174 and 216, which formed an eight-stranded beta-barrel in the C domain, while residues affecting the v.1 epitopes included amino acids 121 and 122 of the B domain. Pairs of MAbs were bactericidal when their respective epitopes involved residues separated by 16 to 20 Å and when at least one of the MAbs inhibited the binding of fH, a downregulatory complement protein. In contrast, there was no cooperative bactericidal activity when the distance between residues was ≥27 Å or ≤14 Å, which correlated with the inhibition of the binding of one MAb by the other MAb. Thus, a model for anti-fH MAb bactericidal activity against strains expressing low levels of fHbp requires the binding of two MAbs directed at nonoverlapping epitopes, which activates the classical complement pathway as well as inhibits fH binding. The latter increases the susceptibility of the organism to complement-mediated bacteriolysis.

scholarly journals A Novel Monoclonal Antibody against FbaA Can Inhibit the Binding of the Complement Regulatory Protein Factor H to Group A Streptococcus

2011 ◽  
Vol 18 (4) ◽  
pp. 552-558 ◽  
Author(s):  
Cuiqing Ma ◽  
Yiyang Guo ◽  
Haiyan Gu ◽  
Ling Zhang ◽  
Hainan Liu ◽  
...  
Keyword(s):  
Amino Acid ◽  
Competitive Inhibition ◽  
Group A Streptococcus ◽  
Regulatory Protein ◽  
Factor H ◽  
Microbial Pathogens ◽  
Enzyme Linked Immunosorbent Assay ◽  
Amino Acid Residues ◽  
Protein Factor ◽  
Group A

ABSTRACTSome microbial pathogens utilize human complement regulatory proteins, such as factor H (FH) and factor H-like protein 1 (FHL-1), for immune evasion. FbaA is an FHL-1 and FH binding protein expressed on the surface of group A streptococcus (GAS), a common agent of pharyngeal, skin, and soft tissue infections. In this study, we prepared monoclonal antibodies (MAbs) against FbaA, assayed them for specificity, and located their binding domains in FbaA. We found an MAb called FbaA MAb2, which demonstrated the highest affinity to GAS among all of the MAbs. Based on the binding with component peptides, the detected epitope, which was specific for FbaA MAb2, was the amino acid residues 95 to 118 of FbaA; on the other hand, it did not bind with the truncated protein of the internally deleted residues of the segment from 95 to 118 of FbaA. Furthermore, the predominant amino acids specific for FbaA MAb2 screened by phage display epitope library were I, T, P, D, and L, corresponding to the amino acid residues 101, 103, 105, 106, and 110 of FbaA, respectively. The binding location of FbaA with FH and FHL-1 was a 16-amino-acid region corresponding to amino acid residues 97 to 112 of FbaA, which overlapped the FbaA MAb2 binding domain, as confirmed by competitive inhibition enzyme-linked immunosorbent assay and immunofluorescence microscopy. Based on the results of the invasion assay, FbaA MAb2 can inhibit the binding of FH to GAS.

scholarly journals Complement Regulatory Protein Factor H Is a Soluble Prion Receptor That Potentiates Peripheral Prion Pathogenesis

2017 ◽  
Vol 199 (11) ◽  
pp. 3821-3827 ◽  
Author(s):  
Sarah J. Kane ◽  
Taylor K. Farley ◽  
Elizabeth O. Gordon ◽  
Joshua Estep ◽  
Heather R. Bender ◽  
...  
Keyword(s):  
Regulatory Protein ◽  
Factor H ◽  
Complement Regulatory Protein ◽  
Protein Factor

scholarly journals Meningococcal Antigen Typing System (MATS)-Based Neisseria meningitidis Serogroup B Coverage Prediction for the MenB-4C Vaccine in the United States

mSphere ◽  
2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Gowrisankar Rajam ◽  
Maria Stella ◽  
Ellie Kim ◽  
Simon Paulos ◽  
Giuseppe Boccadifuoco ◽  
...  
Keyword(s):  
United States ◽  
Vaccine Coverage ◽  
Binding Protein ◽  
The United States ◽  
Factor H ◽  
Enzyme Linked Immunosorbent Assay ◽  
Immune Reactivity ◽  
Content Type ◽  
Efficacy Trials ◽  
Typing System

ABSTRACT The meningococcal antigen typing system (MATS) is an enzyme-linked immunosorbent assay (ELISA)-based system that assesses the levels of expression and immune reactivity of the three recombinant MenB-4C antigens and, in conjunction with PorA variable 2 (VR2) sequencing, provides an estimate of the susceptibility of NmB isolates to killing by MenB-4C-induced antibodies. MATS assays or similar antigen phenotype analyses assume importance under conditions in which analyses of vaccine coverage predictions are not feasible with existing strategies, including large efficacy trials or functional antibody screening of an exhaustive strain panel. MATS screening of a panel of NmB U.S. isolates (n = 442) predicts high MenB-4C vaccine coverage in the United States. Neisseria meningitidis is the most common cause of bacterial meningitis in children and young adults worldwide. A 4-component vaccine against N. meningitidis serogroup B (MenB) disease (MenB-4C [Bexsero]; GSK) combining factor H binding protein (fHBP), neisserial heparin binding protein (NHBA), neisserial adhesin A (NadA), and PorA-containing outer membrane vesicles was recently approved for use in the United States and other countries worldwide. Because the public health impact of MenB-4C in the United States is unclear, we used the meningococcal antigen typing system (MATS) to assess the strain coverage in a panel of strains representative of serogroup B (NmB) disease in the United States. MATS data correlate with killing in the human complement serum bactericidal assay (hSBA) and predict the susceptibility of NmB strains to killing in the hSBA, the accepted correlate of protection for MenB-4C vaccine. A panel of 442 NmB United States clinical isolates (collected in 2000 to 2008) whose data were down weighted with respect to the Oregon outbreak was selected from the Active Bacterial Core Surveillance (ABCs; CDC, Atlanta, GA) laboratory. MATS results examined to determine strain coverage were linked to multilocus sequence typing and antigen sequence data. MATS predicted that 91% (95% confidence interval [CI95], 72% to 96%) of the NmB strains causing disease in the United States would be covered by the MenB-4C vaccine, with the estimated coverage ranging from 88% to 97% by year with no detectable temporal trend. More than half of the covered strains could be targeted by two or more antigens. NHBA conferred coverage to 83% (CI95, 45% to 93%) of the strains, followed by factor H-binding protein (fHbp), which conferred coverage to 53% (CI95, 46% to 57%); PorA, which conferred coverage to 5.9%; and NadA, which conferred coverage to 2.5% (CI95, 1.1% to 5.2%). Two major clonal complexes (CC32 and CC41/44) had 99% strain coverage. The most frequent MATS phenotypes (39%) were fHbp and NHBA double positives. MATS predicts over 90% MenB-4C strain coverage in the United States, and the prediction is stable in time and consistent among bacterial genotypes. IMPORTANCE The meningococcal antigen typing system (MATS) is an enzyme-linked immunosorbent assay (ELISA)-based system that assesses the levels of expression and immune reactivity of the three recombinant MenB-4C antigens and, in conjunction with PorA variable 2 (VR2) sequencing, provides an estimate of the susceptibility of NmB isolates to killing by MenB-4C-induced antibodies. MATS assays or similar antigen phenotype analyses assume importance under conditions in which analyses of vaccine coverage predictions are not feasible with existing strategies, including large efficacy trials or functional antibody screening of an exhaustive strain panel. MATS screening of a panel of NmB U.S. isolates (n = 442) predicts high MenB-4C vaccine coverage in the United States.

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