Characterization of Human Monoclonal Antibodies Specific to the Hepatitis C Virus Glycoprotein E2 within VitroBinding Neutralization Properties

Habersetzer, François; Fournillier, Anne; Dubuisson, Jean; Rosa, Domenico; Abrignani, Sergio; Wychowski, Czeslaw; Nakano, Isao; Trépo, Christian; Des̀granges, Claude; Inchauspé, Geneviève

doi:10.1006/viro.1998.9202

Cited by 77 publications

(52 citation statements)

References 47 publications

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“…Furthermore, Fab e137 did not bind to recombinant maltosebinding protein-E2 fusion protein or to hypervariable region (HVR) multiple antigenic peptides using an enzyme-linked immunosorbent assay (ELISA) (data not shown). These data suggest that e137 is directed against a conformational epitope retained in the full-length HCV E2, as usually seen in broadly neutralizing antibodies (1,5,17,18). Accordingly, as an alternative strategy for mapping the epitope recognized by e137, we used an ELISA competition assay with a panel of mouse and rat MAbs directed against known epitopes of genotype 1a HCV E2 (Table 1).…”

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confidence: 99%

Identification of a Broadly Cross-Reacting and Neutralizing Human Monoclonal Antibody Directed against the Hepatitis C Virus E2 Protein

Perotti

Mancini

Diotti

et al. 2008

J Virol

113

110

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Identification of anti-hepatitis C virus (anti-HCV) human antibody clones with broad neutralizing activity is important for a better understanding of the interplay between the virus and host and for the design of an effective passive immunotherapy and an effective vaccine. We report the identification of a human monoclonal Fab (e137) able to bind the HCV E2 glycoprotein of all HCV genotypes but genotype 5. The results of antibody competition assays and testing the reactivity to alanine mutant E2 proteins confirmed that the e137 epitope includes residues (T416, W420, W529, G530, and D535) highly conserved across all HCV genotypes. Fab e137 neutralized HCV pseudoparticles bearing genotype 1a, 1b, and 4 E1-E2 proteins and to a lesser extent, genotype 2b. Fab e137 was also able to inhibit cell culture-grown HCV (genotype 2a). These data indicate that broadly cross-reacting and cross-neutralizing antibodies are generated during HCV infection.

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confidence: 99%

Identification of a Broadly Cross-Reacting and Neutralizing Human Monoclonal Antibody Directed against the Hepatitis C Virus E2 Protein

Perotti

Mancini

Diotti

et al. 2008

J Virol

113

110

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“…Most antibodies that demonstrate broad neutralization of cell binding and/or infection are directed against conformational epitopes within E2. [27][28][29][30][31] Induction of antibodies recognizing conformational epitopes is a challenging task, as these are difficult to mimic, and protein subunit vaccines are more likely to generate strain-restricted responses due to the immuno-dominance of the variable regions. 32 However, we have recently shown that the mouse monoclonal antibody (MAb) AP33 can potently neutralize retroviral pseudo-particles (HCVpp) bearing genetically diverse E1E2 glycoproteins.…”

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confidence: 99%

Characterization of the hepatitis C virus E2 epitope defined by the broadly neutralizing monoclonal antibody AP33

et al. 2006

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The mouse monoclonal antibody (MAb) AP33, recognizing a 12 amino acid linear epitope in the hepatitis C virus (HCV) E2 glycoprotein, potently neutralizes retroviral pseudoparticles (HCVpp) carrying genetically diverse HCV envelope glycoproteins. Consequently, this antibody and its epitope are highly relevant to vaccine design and immunotherapeutic development. The rational design of immunogens capable of inducing antibodies that target the AP33 epitope will benefit from a better understanding of this region. We have used complementary approaches, which include random peptide phage display mapping and alanine scanning mutagenesis, to identify residues in the HCV E2 protein critical for MAb AP33 binding. Four residues crucial for MAb binding were identified, which are highly conserved in HCV E2 sequences. Three residues within E2 were shown to be critical for binding to the rat MAb 3/11, which previously was shown to recognize the same 12 amino acid E2 epitope as MAb AP33 antibody, although only two of these were shared with MAb AP33. MAb AP33 bound to a panel of functional E2 proteins representative of genotypes 1-6 with higher affinity than MAb 3/11. Similarly, MAb AP33 was consistently more efficient at neutralizing infectivity by diverse HCVpp than MAb 3/11. Importantly, MAb AP33 was also able to neutralize the cell culture infectious HCV clone JFH-1. In conclusion, these data identify important protective determinants and will greatly assist the development of vaccine candidates based on the AP33 epitope. HCV, a member of the Flaviviridae family, has a 9-kb genome encoding a polyprotein precursor that is cleaved to yield three structural proteins, core, E1, and E2, together with at least six non-structural proteins. E1 and E2 are highly glycosylated membrane-anchored proteins that mediate viral entry. 2-6 E2 has been shown to bind to a number of cell surface molecules. 7-10 Whereas the exact mechanism of viral entry is unknown, mounting evidence indicates that CD81 and SR-BI are key molecules. 2,[4][5][6][11][12][13][14] In an infected individual, HCV exists as a viral quasispecies. 15 HCV can be classified into at least six major genotypes that exhibit extensive genetic variability, particularly in E1 and E2. 16 E1 and E2 are the principle targets for neutralizing antibodies, and identification of protective epitopes conserved across different strains of HCV is a major challenge for vaccine design. 17 A number of antibodies that are capable of blocking E2 binding to cells or cell receptors have been described, 18-23 some of which neutralize HCV entry in animal or in vitro models. 6,[24][25][26] The first hypervariable region of E2 contains potent neutralizing epitopes, and antibodies raised against

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“…These antibodies provide little protection against infection, as the HVR-1 sequence continuously evolves in response to pressure exerted by HVR-1-specific neutralizing antibodies (6, 9). More broadly neutralizing antibodies are usually directed against conformational epitopes in E2 (10)(11)(12)(13)(14). Cross-competition analyses, coupled with alanine scanning studies of recombinant antigens, have delineated at least three immunogenic clusters of overlapping epitopes bound by functionally distinct groups of monoclonal antibodies (mAbs) isolated from infected humans (15).…”

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In vitro selection of a neutralization-resistant hepatitis C virus escape mutant

Gal-Tanamy

Keck

et al. 2008

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

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Effective immunization against hepatitis C virus (HCV) infections is likely to require the induction of both robust T and B cell immunity. Although neutralizing antibodies may play an important role in control of infection, there is little understanding of the structure of the HCV envelope glycoproteins and how they interact with such antibodies. An additional challenge for vaccine design is the genetic diversity of HCV and the rapid evolution of viral quasispecies that escape antibody-mediated neutralization. We used a cell culture-infectious, chimeric HCV with the structural proteins of genotype 1a virus to identify envelope residues contributing to the epitope recognized by a broadly neutralizing, murine monoclonal antibody, AP33. By repetitive rounds of neutralization followed by amplification, we selected a population of viral escape mutants that resist stringent neutralization with AP33 and no longer bind the antibody. Two amino acid substitutions, widely separated in the linear sequence of the E2 envelope protein (N415Y and E655G), were identified by sequencing of cloned cDNA and shown by reverse genetics analysis to contribute jointly to the AP33 resistance phenotype. The N415Y mutation substantially lowered virus fitness, most likely because of a defect in viral entry, but did not reduce binding of soluble CD81 to immobilized HCV-pseudotyped retrovirus particles. The in vitro selection of an HCV escape mutant recapitulates the ongoing evolution of antigenic variants that contributes to viral persistence in humans and reveals information concerning the conformational structure of the AP33 epitope, its role in viral replication, and constraints on its molecular evolution.antibody ͉ immunity ͉ vaccine ͉ viral envelope

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Characterization of Human Monoclonal Antibodies Specific to the Hepatitis C Virus Glycoprotein E2 within VitroBinding Neutralization Properties

Cited by 77 publications

References 47 publications

Identification of a Broadly Cross-Reacting and Neutralizing Human Monoclonal Antibody Directed against the Hepatitis C Virus E2 Protein

Identification of a Broadly Cross-Reacting and Neutralizing Human Monoclonal Antibody Directed against the Hepatitis C Virus E2 Protein

Characterization of the hepatitis C virus E2 epitope defined by the broadly neutralizing monoclonal antibody AP33

In vitro selection of a neutralization-resistant hepatitis C virus escape mutant

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