Protective Antibody Responses Elicited by a Meningococcal Outer Membrane Vesicle Vaccine with Overexpressed Genome‐Derived Neisserial Antigen 1870

Hou, Victor C.; Koeberling, Oliver; Welsch, Jo Anne; Granoff, Dan M.

doi:10.1086/432102

Cited by 50 publications

(48 citation statements)

References 35 publications

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“…Our hypothesis is that the fHbp NOMV vaccines elicited a different anti-fHbp antibody repertoire than the recombinant fHbp vaccine, which can affect bactericidal activity (3,4). An alternative hypothesis is that there were different anti-fHbp IgG subclass responses to the different vaccine formulations, but previously published data did not support this possibility (19). A third possibility was that antibodies directed at other antigens in the NOMV vaccine augmented bactericidal activity of the anti-fHbp antibodies.…”

Section: Discussionmentioning

confidence: 88%

“…The endogenous fHbp-encoding gene was replaced with an erythromycin cassette, which generated recombinant strains ⌬LpxL1 ⌬fHbp and ⌬LpxL1⌬fHbp-FNR c , respectively. A second fHbp-overexpressing strain was generated by transforming ⌬LpxL1⌬fHbp with the multicopy plasmid pFP12-gna1870, (19) which in this study was renamed pFP12-fHbp. The plasmid contained the gene encoding fHbp ID 1 and resulted in 10-fold-increased fHbp expression (10ϫ fHbp) (see Results).…”

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confidence: 99%

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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

Koeberling

Delany

Granoff³

2011

Clin. Vaccine Immunol.

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Native 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 (⌬LpxL1) 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 ⌬LpxL1/⌬fHbp 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 ⌬fHbp 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.

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Section: Discussionmentioning

confidence: 88%

mentioning

confidence: 99%

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

Koeberling

Delany

Granoff³

2011

Clin. Vaccine Immunol.

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“…fH/murine Fc fusion constructs were used to examine the binding of fH to fHbp. These constructs contained contiguous fH SCR domains (SCR 1-5, 1-6, 5-8, 6-10, 11-15, or [16][17][18][19][20] fused in frame at their C-terminal ends to the N terminus of the Fc fragment of murine immunoglobulin G2a (IgG2a) (fH/Fc fusion proteins). The construction of these chimeric fH/murine Fc fusion proteins and the estimation of the concentration of the fusion proteins in concentrated cell culture supernatants have been described in detail previously (34).…”

Section: Methodsmentioning

confidence: 99%

“…To determine the functional consequences of these differences, we compared C3 deposition at different time points after the exposure of organisms to NHS. The amounts of C3 binding to Y2220 siaD por F62 (binds fH through SCR [16][17][18][19][20] and Y2220 siaD fHbp H44/76 (binds fH through SCR 6) were compared after bacteria were incubated with NHS. The expression of Por F62 more effectively limited deposition of C3 than the expression of fHbp H44/76 (Fig.…”

Section: Comparison Of Fh Binding To Meningococcal Fhbp and Gonococcamentioning

confidence: 99%

Functional Comparison of the Binding of Factor H Short Consensus Repeat 6 (SCR 6) to Factor H Binding Protein fromNeisseria meningitidisand the Binding of Factor H SCR 18 to 20 toNeisseria gonorrhoeaePorin

et al. 2009

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Both Neisseria meningitidis and Neisseria gonorrhoeae recruit the alternative pathway complement inhibitory protein factor H (fH) to their surfaces to evade complement-dependent killing. Meningococci bind fH via fH binding protein (fHbp), a surface-exposed lipoprotein that is subdivided into three variant families based on one classification scheme. Chimeric proteins that comprise contiguous domains of fH fused to murine Fc were used to localize the binding site for all three fHbp variants on fH to short consensus repeat 6 (SCR 6). As expected, fH-like protein 1 (FHL-1), which contains fH SCR 6, also bound to fHbp-expressing meningococci. Using site-directed mutagenesis, we identified histidine 337 and histidine 371 in SCR 6 as important for binding to fHbp. These findings may provide the molecular basis for recent observations that demonstrated human-specific fH binding to meningococci. Differences in the interactions of fHbp variants with SCR 6 were evident. Gonococci bind fH via their porin (Por) molecules (PorB.1A or PorB.1B); sialylation of lipooligosaccharide enhances fH binding. Both sialylated PorB.1B-and (unsialylated) PorB.1A-bearing gonococci bind fH through SCR 18 to 20; PorB.1A can also bind SCR 6, but only weakly, as evidenced by a low level of binding of FHL-1 relative to that of fH. Using isogenic strains expressing either meningococcal fHbp or gonococcal PorB.1B, we discovered that strains expressing gonococcal PorB.1B in the presence of sialylated lipooligosaccharide bound more fH, more effectively limited C3 deposition, and were more serum resistant than their isogenic counterparts expressing fHbp. Differences in fH binding to these two related pathogens may be important for modulating their individual responses to host immune attack.

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“…Recombinant fHBP (rLP2086) is the principal antigen of another MenB vaccine containing recombinant proteins from two different variant subfamilies (16,56). More recent studies also support the strategy to prepare native OMV vaccines from mutant strains engineered to express different fHBP alleles that would confer broad protection against meningococcal strains expressing fHBP from each of the antigenic variant groups (22,25).…”

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confidence: 96%

Expression of Factor H Binding Protein of Meningococcus Responds to Oxygen Limitation through a Dedicated FNR-Regulated Promoter

2010

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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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Protective Antibody Responses Elicited by a Meningococcal Outer Membrane Vesicle Vaccine with Overexpressed Genome‐Derived Neisserial Antigen 1870

Cited by 50 publications

References 35 publications

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

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

Functional Comparison of the Binding of Factor H Short Consensus Repeat 6 (SCR 6) to Factor H Binding Protein fromNeisseria meningitidisand the Binding of Factor H SCR 18 to 20 toNeisseria gonorrhoeaePorin

Expression of Factor H Binding Protein of Meningococcus Responds to Oxygen Limitation through a Dedicated FNR-Regulated Promoter

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