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 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 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 A Critical Threshold of Meningococcal Factor H Binding Protein Expression Is Required for Increased Breadth of Protective Antibodies Elicited by Native Outer Membrane Vesicle Vaccines

2011 ◽  
Vol 18 (5) ◽  
pp. 736-742 ◽  
Author(s):  
Oliver Koeberling ◽  
Isabel Delany ◽  
Dan M. Granoff
Keyword(s):  
Outer Membrane ◽  
Binding Protein ◽  
Membrane Vesicle ◽  
Membrane Vesicles ◽  
Outer Membrane Vesicles ◽  
Factor H ◽  
Critical Threshold ◽  
Recombinant Strains ◽  
Endotoxin Activity ◽  
Group B

ABSTRACTNative outer membrane vesicles (NOMV) (not detergent treated), which are prepared from recombinant strains with attenuated endotoxin activity and overexpressed factor H binding protein (fHbp), elicited broad serum bactericidal antibody responses in mice. The amount of overexpressed fHbp required for optimal immunogenicity is not known. In this study we prepared NOMV vaccines from LpxL1 knockout (ΔLpxL1) mutants with penta-acylated lipooligosaccharide and attenuated endotoxin activity. The recombinant strains had wild-type (1×) fHbp expression or were engineered for 3-fold- or 10-fold-increased fHbp expression (3× or 10× fHbp). Control vaccines included NOMV from ΔLpxL1/ΔfHbp mutants or recombinant fHbp. In mice, only the 10× fHbp NOMV vaccine elicited significantly higher serum IgG anti-fHbp antibody titers than the corresponding 1× fHbp NOMV or recombinant fHbp vaccine. The 10× fHbp NOMV vaccine also elicited higher bactericidal responses (P< 0.05) against five group B strains with heterologous PorA than the recombinant fHbp or 1× fHbp NOMV vaccine. The 3× fHbp NOMV vaccine gave higher bactericidal titers against only one strain. Serum bactericidal titers in mice immunized with the control ΔfHbp NOMV vaccines were <1:10, and bactericidal titers in mice immunized with the 10× fHbp NOMV vaccine were <1:10 after adsorption of anti-fHbp antibodies. Mixing antiserum to NOMV vaccines from fHbp knockout mutants with antiserum to recombinant fHbp did not increase anti-fHbp bactericidal titers. Thus, a critical threshold of increased fHbp expression is required for NOMV vaccines to elicit broad serum bactericidal responses, and the antibodies conferring protection are directed primarily at fHbp.

scholarly journals Structural basis for cooperativity of human monoclonal antibodies to meningococcal factor H-binding protein

2019 ◽  
Vol 2 (1) ◽  
Author(s):  
Ilaria Peschiera ◽  
Maria Giuliani ◽  
Fabiola Giusti ◽  
Roberto Melero ◽  
Eugenio Paccagnini ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Binding Protein ◽  
Factor H ◽  
Structural Basis ◽  
Human Monoclonal Antibodies

scholarly journals Allelic Diversity of the Two Transferrin Binding Protein B Gene Isotypes among a Collection of Neisseria meningitidisStrains Representative of Serogroup B Disease: Implication for the Composition of a Recombinant TbpB-Based Vaccine

2000 ◽  
Vol 68 (9) ◽  
pp. 4938-4947 ◽  
Author(s):  
Bachra Rokbi ◽  
Geneviève Renauld-Mongenie ◽  
Michèle Mignon ◽  
B. Danve ◽  
David Poncet ◽  
...  
Keyword(s):  
Amino Acids ◽  
Bactericidal Activity ◽  
Immunoglobulin G ◽  
Binding Protein ◽  
Restriction Analysis ◽  
Allelic Diversity ◽  
Gene Variants ◽  
C Terminus ◽  
Specific Antisera

ABSTRACT The distribution of the two isotypes of tbpB in a collection of 108 serogroup B meningococcal strains belonging to the four major clonal groups associated with epidemic and hyperendemic disease (the ET-37 complex, the ET-5 complex, lineage III, and cluster A4) was determined. Isotype I strains (with a 1.8-kbtbpB gene) was less represented than isotype II strains (19.4 versus 80.6%). Isotype I was restricted to the ET-37 complex strains, while isotype II was found in all four clonal complexes. The extent of the allelic diversity of tbpB in these two groups was studied by PCR restriction analysis and sequencing of 10 newtbpB genes. Four major tbpB gene variants were characterized: B16B6 (representative of isotype I) and M982, BZ83, and 8680 (representative of isotype II). The relevance of these variants was assessed at the antigenic level by the determination of cross-bactericidal activity of purified immunoglobulin G preparations raised to the corresponding recombinant TbpB (rTbpB) protein against a panel of 27 strains (5 of isotype I and 22 of isotype II). The results indicated that rTbpB corresponding to each variant was able to induce cross-bactericidal antibodies. However, the number of strains killed with an anti-rTbpB serum was slightly lower than that obtained with an anti-TbpA+B complex. None of the sera tested raised against an isotype I strain was able to kill an isotype II strain and vice versa. None of the specific antisera tested (anti-rTbpB or anti-TbpA+B complex) was able to kill all of the 22 isotype II strains tested. Moreover, using sera raised against the C-terminus domain of TbpB M982 (amino acids 352 to 691) or BZ83 (amino acids 329 to 669) fused to the maltose-binding protein, cross-bactericidal activity was detected against 12 and 7 isotype II strains, respectively, of the 22 tested. These results suggest surface accessibility of the C-terminal end of TbpB. Altogether, these results show that although more than one rTbpB will be required in the composition of a TbpB-based vaccine to achieve a fully cross-bactericidal activity, rTbpB and its C terminus were able by themselves to induce cross-bactericidal antibodies.

Influence of sequence variability on bactericidal activity sera induced by Factor H binding protein variant 1.1

Vaccine ◽  
2011 ◽  
Vol 29 (5) ◽  
pp. 1072-1081 ◽  
Author(s):  
Brunella Brunelli ◽  
Elena Del Tordello ◽  
Emmanuelle Palumbo ◽  
Alessia Biolchi ◽  
Stefania Bambini ◽  
...  
Keyword(s):  
Bactericidal Activity ◽  
Binding Protein ◽  
Factor H ◽  
Sequence Variability ◽  
Protein Variant

scholarly journals Molecular characterization of two sub-family specific monoclonal antibodies to meningococcal Factor H binding protein

Heliyon ◽  
2018 ◽  
Vol 4 (4) ◽  
pp. e00591 ◽  
Author(s):  
C. Lo Passo ◽  
L. Zippilli ◽  
A. Angiolillo ◽  
I. Costa ◽  
I. Pernice ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Molecular Characterization ◽  
Binding Protein ◽  
Factor H

scholarly journals Human Factor H (FH) Impairs Protective Meningococcal Anti-FHbp Antibody Responses and the Antibodies Enhance FH Binding

mBio ◽  
2014 ◽  
Vol 5 (5) ◽  
Author(s):  
Isabella Costa ◽  
Rolando Pajon ◽  
Dan M. Granoff
Keyword(s):  
Transgenic Mice ◽  
Bactericidal Activity ◽  
Binding Protein ◽  
Vaccine Safety ◽  
Factor H ◽  
Antibody Responses ◽  
Wild Type ◽  
Serum Samples ◽  
Serum Bactericidal Activity ◽  
4Cmenb Vaccine

ABSTRACT The meningococcal 4CMenB vaccine (Bexsero; Novartis) contains four antigens that can elicit serum bactericidal activity, one of which is factor H (FH)-binding protein (FHbp). FHbp specifically binds human complement FH. When humans are immunized, FHbp is expected to form a complex with FH, which could affect immunogenicity and safety. Wild-type mice (whose FH does not bind to FHbp) and human FH transgenic mice were immunized with three doses of 4CMenB, and their responses were compared. There were no significant differences between the serum bactericidal responses of transgenic and wild-type mice to strains with all of the antigens mismatched for 4CMenB except PorA or NadA. In contrast, against a strain mismatched for all of the antigens except FHbp, the transgenic mice had 15-fold weaker serum bactericidal antibody responses (P = 0.0006). Binding of FH downregulates complement. One explanation for the lower anti-FHbp serum bactericidal activity in the transgenic mice is that their postimmunization serum samples enhanced the binding of FH to FHbp, whereas the serum samples from the wild-type mice inhibited FH binding. Control antiserum from transgenic mice immunized with a low-FH-binding mutant FHbp (R41S) vaccine inhibited FH binding. Two 4CMenB-vaccinated transgenic mice developed serum IgM autoantibodies to human FH. Thus, human FH impairs protective serum anti-FHbp antibody responses, in part by skewing the antibody repertoire to FHbp epitopes outside the FH binding site. FHbp vaccines that bind FH may elicit FH autoantibodies. Mutant FHbp antigens with low FH binding could improve protection and, potentially, vaccine safety in humans. IMPORTANCE Two serogroup B meningococcal vaccines contain a novel antigen called factor H (FH)-binding protein (FHbp). FHbp specifically binds human FH, a plasma protein that downregulates complement. One vaccine (4CMenB; Novartis) is licensed in Europe, Canada, and Australia. When humans are immunized, FHbp can complex with FH. We compared the immunogenicity of 4CMenB vaccine in wild-type mice, whose own FH does not bind to FHbp, and human FH transgenic mice. Transgenic mice had respective antibody responses similar to those of wild-type mice to 4CMenB antigens that do not bind FH. However, the protective antibody responses of the transgenic mice to FHbp were impaired, largely because the antibodies did not inhibit but rather enhanced the binding of FH to FHbp. Two transgenic mice developed serum IgM autoantibodies to FH. Mutant FHbp antigens with low FH binding likely will elicit greater protection in humans than FHbp vaccines that bind FH and have a lower risk of FH autoantibodies.

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