scholarly journals Escape of Hepatitis C Virus from Epitope I Neutralization Increases Sensitivity of Other Neutralization Epitopes

2018 ◽  
Vol 92 (9) ◽  
Author(s):  
Jun Gu ◽  
Joshua Hardy ◽  
Irene Boo ◽  
Patricia Vietheer ◽  
Kathleen McCaffrey ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Vaccine Development ◽  
Acquired Resistance ◽  
Neutralizing Antibody ◽  
Cell Surface Receptor ◽  
Antigenic Determinants ◽  
Surface Receptor ◽  
Broadly Neutralizing Antibody ◽  
First Time

ABSTRACTThe hepatitis C virus (HCV) E2 glycoprotein is a major target of the neutralizing antibody (nAb) response, with multiple type-specific and broadly neutralizing antibody (bnAb) epitopes identified. The 412-to-423 region can generate bnAbs that block interaction with the cell surface receptor CD81, with activity toward multiple HCV genotypes. In this study, we reveal the structure of rodent monoclonal antibody 24 (MAb24) with an extensive contact area toward a peptide spanning the 412-to-423 region. The crystal structure of the MAb24–peptide 412-to-423 complex reveals the paratope bound to a peptide hairpin highly similar to that observed with human MAb HCV1 and rodent MAb AP33, but with a different angle of approach. In viral outgrowth experiments, we demonstrated three distinct genotype 2a viral populations that acquired resistance to MAb24 via N415D, N417S, and N415D/H386R mutations. Importantly, the MAb24-resistant viruses exhibited significant increases in sensitivity to the majority of bnAbs directed to epitopes within the 412-to-423 region and in additional antigenic determinants located within E2 and the E1E2 complex. This study suggests that modification of N415 causes a global change in glycoprotein structure that increases its vulnerability to neutralization by other antibodies. This finding suggests that in the context of an antibody response to viral infection, acquisition of escape mutations in the 412-to-423 region renders the virus more susceptible to neutralization by other specificities of nAbs, effectively reducing the immunological fitness of the virus. A vaccine for HCV that generates polyspecific humoral immunity with specificity for the 412-to-423 region and at least one other region of E2 is desirable.IMPORTANCEUnderstanding how antibodies neutralize hepatitis C virus (HCV) is essential for vaccine development. This study reveals for the first time that when HCV develops resistance to a major class of bnAbs targeting the 412-to-423 region of E2, this results in a concomitant increase in sensitivity to neutralization by a majority of other bnAb specificities. Vaccines for the prevention of HCV infection should therefore generate bnAbs directed toward the 412-to-423 region of E2 and additional bnAb epitopes within the viral glycoproteins.

scholarly journals Monoclonal Antibody AP33 Defines a Broadly Neutralizing Epitope on the Hepatitis C Virus E2 Envelope Glycoprotein

2005 ◽  
Vol 79 (17) ◽  
pp. 11095-11104 ◽  
Author(s):  
Ania Owsianka ◽  
Alexander W. Tarr ◽  
Vicky S. Juttla ◽  
Dimitri Lavillette ◽  
Birke Bartosch ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Envelope Protein ◽  
Hypervariable Region ◽  
Neutralizing Antibody ◽  
Broadly Neutralizing Antibody ◽  
New Treatments ◽  
Potent Neutralization

ABSTRACT Hepatitis C virus (HCV) remains a significant threat to the general health of the world's population, and there is a pressing need for the development of new treatments and preventative vaccines. Here, we describe the generation of retrovirus-based pseudoparticles (HCVpp) incorporating a panel of full-length E1E2 clones representative of the major genotypes 1 through 6, and their application to assess the reactivity and neutralizing capability of antisera and monoclonal antibodies raised against portions of the HCV E2 envelope protein. Rabbit antisera raised against either the first hypervariable region or ectodomain of E2 showed limited and strain specific neutralization. By contrast, the monoclonal antibody (MAb) AP33 demonstrated potent neutralization of infectivity against HCVpp carrying E1E2 representative of all genotypes tested. The concentration of AP33 required to achieve 50% inhibition of infection by HCVpp of diverse genotypes ranged from 0.6 to 32 μg/ml. The epitope recognized by MAb AP33 is linear and highly conserved across different genotypes of HCV. Thus, identification of a broadly neutralizing antibody that recognizes a linear epitope is likely to be of significant benefit to future vaccine and therapeutic antibody development.

scholarly journals Broad Anti-Hepatitis C Virus (HCV) Antibody Responses Are Associated with Improved Clinical Disease Parameters in Chronic HCV Infection

2016 ◽  
Vol 90 (9) ◽  
pp. 4530-4543 ◽  
Author(s):  
Rachael E. Swann ◽  
Vanessa M. Cowton ◽  
Mark W. Robinson ◽  
Sarah J. Cole ◽  
Stephen T. Barclay ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Chronic Infection ◽  
Neutralizing Antibodies ◽  
Neutralizing Antibody ◽  
Hcv Infection ◽  
Neutralization Activity ◽  
Broadly Neutralizing Antibody ◽  
Chronic Hcv Infection ◽  
Chronic Hcv

ABSTRACTDuring hepatitis C virus (HCV) infection, broadly neutralizing antibody (bNAb) responses targeting E1E2 envelope glycoproteins are generated in many individuals. It is unclear if these antibodies play a protective or a pathogenic role during chronic infection. In this study, we investigated whether bNAb responses in individuals with chronic infection were associated with differences in clinical presentation. Patient-derived purified serum IgG was used to assess the breadth of HCV E1E2 binding and the neutralization activity of HCV pseudoparticles. The binding and neutralization activity results for two panels bearing viral envelope proteins representing either an intergenotype or an intragenotype 1 group were compared. We found that the HCV load was negatively associated with strong cross-genotypic E1E2 binding (P= 0.03). Overall, we observed only a modest correlation between total E1E2 binding and neutralization ability. The breadth of intergenotype neutralization did not correlate with any clinical parameters; however, analysis of individuals with genotype 1 (gt1) HCV infection (n= 20), using an intragenotype pseudoparticle panel, found a strong association between neutralization breadth and reduced liver fibrosis (P= 0.006). A broad bNAb response in our cohort with chronic infection was associated with a single nucleotide polymorphism (SNP) in theHLA-DQB1gene (P= 0.038), as previously reported in a cohort with acute disease. Furthermore, the bNAbs in these individuals targeted more than one region of E2-neutralizing epitopes, as assessed through cross-competition of patient bNAbs with well-characterized E2 antibodies. We conclude that the bNAb responses in patients with chronic gt1 infection are associated with lower rates of fibrosis and host genetics may play a role in the ability to raise such responses.IMPORTANCEGlobally, there are 130 million to 150 million people with chronic HCV infection. Typically, the disease is progressive and is a major cause of severe liver cirrhosis and hepatocellular carcinoma. While it is known that neutralizing antibodies have a role in spontaneous clearance during acute infection, little is known about their role in chronic infection. In the present work, we investigated the antibody response in a cohort of chronically infected individuals and found that a broadly neutralizing antibody response is protective and is associated with reduced levels of liver fibrosis and cirrhosis. We also found an association between SNPs in class II HLA genes and the presence of a broadly neutralizing response, indicating that antigen presentation may be important for the production of HCV-neutralizing antibodies.

scholarly journals Toward a Hepatitis C Virus Vaccine: the Structural Basis of Hepatitis C Virus Neutralization by AP33, a Broadly Neutralizing Antibody

2012 ◽  
Vol 86 (23) ◽  
pp. 12923-12932 ◽  
Author(s):  
J. A. Potter ◽  
A. M. Owsianka ◽  
N. Jeffery ◽  
D. J. Matthews ◽  
Z.-Y. Keck ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Vaccine ◽  
Neutralizing Antibody ◽  
Virus Neutralization ◽  
Structural Basis ◽  
Broadly Neutralizing Antibody

scholarly journals Structural basis of hepatitis C virus neutralization by broadly neutralizing antibody HCV1

2012 ◽  
Vol 109 (24) ◽  
pp. 9499-9504 ◽  
Author(s):  
L. Kong ◽  
E. Giang ◽  
J. B. Robbins ◽  
R. L. Stanfield ◽  
D. R. Burton ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Neutralizing Antibody ◽  
Virus Neutralization ◽  
Structural Basis ◽  
Broadly Neutralizing Antibody

scholarly journals Broadly Neutralizing Antibody Mediated Clearance of Human Hepatitis C Virus Infection

2018 ◽  
Vol 24 (5) ◽  
pp. 717-730.e5 ◽  
Author(s):  
Valerie J. Kinchen ◽  
Muhammad N. Zahid ◽  
Andrew I. Flyak ◽  
Mary G. Soliman ◽  
Gerald H. Learn ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Virus Infection ◽  
Neutralizing Antibody ◽  
Hepatitis C Virus Infection ◽  
Human Hepatitis ◽  
Broadly Neutralizing Antibody

scholarly journals Identification of Conserved Residues in the E2 Envelope Glycoprotein of the Hepatitis C Virus That Are Critical for CD81 Binding

2006 ◽  
Vol 80 (17) ◽  
pp. 8695-8704 ◽  
Author(s):  
Ania M. Owsianka ◽  
Judith M. Timms ◽  
Alexander W. Tarr ◽  
Richard J. P. Brown ◽  
Timothy P. Hickling ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Envelope Glycoprotein ◽  
Viral Envelope ◽  
Cell Surface Receptor ◽  
Conserved Residues ◽  
Mutant Proteins ◽  
Surface Receptor ◽  
Cd81 Binding

ABSTRACT Hepatitis C virus (HCV) cell entry involves interaction between the viral envelope glycoprotein E2 and the cell surface receptor CD81. Knowledge of conserved E2 determinants important for successful binding will facilitate development of entry inhibitors designed to block this interaction. Previous studies have assigned the CD81 binding function to a number of discontinuous regions of E2. To better define specific residues involved in receptor binding, a panel of mutants of HCV envelope proteins was generated, where conserved residues within putative CD81 binding regions were sequentially mutated to alanine. Mutant proteins were tested for binding to a panel of monoclonal antibodies and CD81 and for their ability to form noncovalent heterodimers and confer infectivity in the retroviral pseudoparticle (HCVpp) assay. Detection by conformation-sensitive monoclonal antibodies indicated that the mutant proteins were correctly folded. Mutant proteins fell into three groups: those that bound CD81 and conferred HCVpp infectivity, those that abrogated both CD81 binding and HCVpp infectivity, and a final group containing mutants that were able to bind CD81 but were noninfectious in the HCVpp assay. Specific amino acids conserved across all genotypes that were critical for CD81 binding were W420, Y527, W529, G530, and D535. These data significantly increase our understanding of the CD81 receptor-E2 binding process.

scholarly journals Antigenicity and Immunogenicity of Differentially Glycosylated Hepatitis C Virus E2 Envelope Proteins Expressed in Mammalian and Insect Cells

2019 ◽  
Vol 93 (7) ◽  
Author(s):  
Richard A. Urbanowicz ◽  
Ruixue Wang ◽  
John E. Schiel ◽  
Zhen-yong Keck ◽  
Melissa C. Kerzic ◽  
...  
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Insect Cell ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Neutralizing Antibody ◽  
Antibody Responses ◽  
Glycosylation Sites ◽  
Complete Deletion ◽  
Global Health Challenge

ABSTRACTThe development of a prophylactic vaccine for hepatitis C virus (HCV) remains a global health challenge. Cumulative evidence supports the importance of antibodies targeting the HCV E2 envelope glycoprotein to facilitate viral clearance. However, a significant challenge for a B cell-based vaccine is focusing the immune response on conserved E2 epitopes capable of eliciting neutralizing antibodies not associated with viral escape. We hypothesized that glycosylation might influence the antigenicity and immunogenicity of E2. Accordingly, we performed head-to-head molecular, antigenic, and immunogenic comparisons of soluble E2 (sE2) produced in (i) mammalian (HEK293) cells, which confer mostly complex- and high-mannose-type glycans; and (ii) insect (Sf9) cells, which impart mainly paucimannose-type glycans. Mass spectrometry demonstrated that all 11 predictedN-glycosylation sites were utilized in both HEK293- and Sf9-derived sE2, but thatN-glycans in insect sE2 were on average smaller and less complex. Both proteins bound CD81 and were recognized by conformation-dependent antibodies. Mouse immunogenicity studies revealed that similar polyclonal antibody responses were generated against antigenic domains A to E of E2. Although neutralizing antibody titers showed that Sf9-derived sE2 induced moderately stronger responses than did HEK293-derived sE2 against the homologous HCV H77c isolate, the two proteins elicited comparable neutralization titers against heterologous isolates. Given that global alteration of HCV E2 glycosylation by expression in different hosts did not appreciably affect antigenicity or overall immunogenicity, a more productive approach to increasing the antibody response to neutralizing epitopes may be complete deletion, rather than just modification, of specificN-glycans proximal to these epitopes.IMPORTANCEThe development of a vaccine for hepatitis C virus (HCV) remains a global health challenge. A major challenge for vaccine development is focusing the immune response on conserved regions of the HCV envelope protein, E2, capable of eliciting neutralizing antibodies. Modification of E2 by glycosylation might influence the immunogenicity of E2. Accordingly, we performed molecular and immunogenic comparisons of E2 produced in mammalian and insect cells. Mass spectrometry demonstrated that the predicted glycosylation sites were utilized in both mammalian and insect cell E2, although the glycan types in insect cell E2 were smaller and less complex. Mouse immunogenicity studies revealed similar polyclonal antibody responses. However, insect cell E2 induced stronger neutralizing antibody responses against the homologous isolate used in the vaccine, albeit the two proteins elicited comparable neutralization titers against heterologous isolates. A more productive approach for vaccine development may be complete deletion of specific glycans in the E2 protein.

scholarly journals Hepatitis C virus vaccine development: old challenges and new opportunities

2015 ◽  
Vol 2 (3) ◽  
pp. 285-295 ◽  
Author(s):  
Dapeng Li ◽  
Zhong Huang ◽  
Jin Zhong
Keyword(s):  
Chronic Hepatitis ◽  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Chronic Hepatitis C ◽  
Vaccine Development ◽  
Rna Virus ◽  
Antiviral Agents ◽  
Resistance Mutations ◽  
Direct Acting Antiviral ◽  
Direct Acting

Abstract Hepatitis C virus (HCV), an enveloped positive-sense single-stranded RNA virus, can cause chronic and end-stage liver diseases. Approximately 185 million people worldwide are infected with HCV. Tremendous progress has been achieved in the therapeutics of chronic hepatitis C thanks to the development of direct-acting antiviral agents (DAAs), but the worldwide use of these highly effective DAAs is limited due to their high treatment cost. In addition, drug-resistance mutations remain a potential problem as DAAs are becoming a standard therapy for chronic hepatitis C. Unfortunately, no vaccine is available for preventing new HCV infection. Therefore, HCV still imposes a big threat to human public health, and the worldwide eradication of HCV is critically dependent on an effective HCV vaccine. In this review, we summarize recent progresses on HCV vaccine development and present our views on the rationale and strategy to develop an effective HCV vaccine.

scholarly journals Extracellular interactions and ligand degradation shape the nodal morphogen gradient

eLife ◽  
2016 ◽  
Vol 5 ◽  
Author(s):  
Yin Wang ◽  
Xi Wang ◽  
Thorsten Wohland ◽  
Karuna Sampath
Keyword(s):  
Correlation Spectroscopy ◽  
Cell Surface Receptor ◽  
Morphogen Gradient ◽  
Axis Formation ◽  
Cellular Interactions ◽  
Fluorescence Correlation ◽  
Selective Ligand ◽  
Surface Receptor ◽  
First Time

The correct distribution and activity of secreted signaling proteins called morphogens is required for many developmental processes. Nodal morphogens play critical roles in embryonic axis formation in many organisms. Models proposed to generate the Nodal gradient include diffusivity, ligand processing, and a temporal activation window. But how the Nodal morphogen gradient forms in vivo remains unclear. Here, we have measured in vivo for the first time, the binding affinity of Nodal ligands to their major cell surface receptor, Acvr2b, and to the Nodal inhibitor, Lefty, by fluorescence cross-correlation spectroscopy. We examined the diffusion coefficient of Nodal ligands and Lefty inhibitors in live zebrafish embryos by fluorescence correlation spectroscopy. We also investigated the contribution of ligand degradation to the Nodal gradient. We show that ligand clearance via degradation shapes the Nodal gradient and correlates with its signaling range. By computational simulations of gradient formation, we demonstrate that diffusivity, extra-cellular interactions, and selective ligand destruction collectively shape the Nodal morphogen gradient.

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