Cross-genotype AR3-specific neutralizing antibodies confer long-term protection in injecting drug users after HCV clearance

doi:10.1016/j.jhep.2019.02.013

Journal of Hepatology

Volume 71, Issue 1, July 2019, Pages 14-24

https://doi.org/10.1016/j.jhep.2019.02.013 Get rights and content

Highlights

•
HCV clearance is associated with a high number of cross-genotype specific antibodies.
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Antigenic region 3 (AR3) is the dominant epitope recognized by the antibodies.
•
AR3-specific antibodies neutralized HCV pseudoparticles and cell culture viruses.
•
A large number of clearers develop antibodies targeting antigenic region 4 (AR4).
•
AR4-specific antibody AT1618 also neutralized neutralization-resistant variants.

Background & Aims

In order to design an effective vaccine against hepatitis C virus (HCV) infection, it is necessary to understand immune protection. A number of broadly reactive neutralizing antibodies have been isolated from B cells of HCV-infected patients. However, it remains unclear whether B cells producing such antibodies contribute to HCV clearance and long-term immune protection against HCV.

Methods

We analysed the B cell repertoire of 13 injecting drug users from the Amsterdam Cohort Study, who were followed up for a median of 17.5 years after primary infection. Individuals were classified into 2 groups based on the outcome of HCV infection: 5 who became chronically infected either after primary infection or after reinfection, and 8 who were HCV RNA negative following spontaneous clearance of ≥1 HCV infection(s). From each individual, 10,000 CD27+IgG+B cells, collected 0.75 year after HCV infection, were cultured to characterize the antibody repertoire.

Results

Using a multiplex flow cytometry-based assay to study the antibody binding to E1E2 from genotype 1 to 6, we found that a high frequency of cross-genotype antibodies was associated with spontaneous clearance of 1 or multiple infections (p = 0.03). Epitope specificity of these cross-genotype antibodies was determined by alanine mutant scanning in 4 individuals who were HCV RNA negative following spontaneous clearance of 1 or multiple infections. Interestingly, the cross-genotype antibodies were mainly antigenic region 3 (AR3)-specific and showed cross-neutralizing activity against HCV. In addition to AR3 antibodies, 3 individuals developed antibodies recognizing antigenic region 4, of which 1 monoclonal antibody showed cross-neutralizing capacity.

Conclusions

Together, these data suggest that a strong B cell response producing cross-genotype and neutralizing antibodies, especially targeting AR3, contributes to HCV clearance and long-term immune protection against HCV.

Lay summary

Although effective treatments against hepatitis C virus (HCV) are available, 500,000 people die from liver disease caused by HCV each year and approximately 1.75 million people are newly infected. This could be prevented by a vaccine. To design a vaccine against HCV, more insight into the role of antibodies in the protection against HCV infection is needed. In a cohort of injecting drug users, we found that antibodies interfering with virus cell entry, and recognizing multiple HCV genotypes, conferred long-term protection against chronic HCV infection.

Graphical abstract

Introduction

Hepatitis C virus (HCV) is one of the major global public health problems, with 71 million chronically infected people worldwide, which results in 350,000 to 500,000 liver-related deaths per year.¹ Current direct-acting antiviral (DAA) treatment is very effective in clearing infection.² However, despite high DAA efficacy, treatment alone is unlikely to eliminate HCV by the year 2030 as envisioned by the World Health Organization (WHO),¹ since treated individuals may become reinfected if exposure continues. Moreover, worldwide, most of the HCV-infected individuals are unaware of their HCV status because of the prolonged asymptomatic nature of HCV infection and limited access to diagnostic tests.³ In addition, as a result of the high cost of treatment, a large proportion of the HCV-infected individuals are left untreated.³ Therefore, for the global elimination of HCV, a preventive vaccine is urgently needed.

Development of a protective vaccine against HCV seems feasible, since spontaneous clearance of the virus without antiviral therapy occurs in 25 to 40% of individuals after primary infection⁴ and in 30 to 60% of those who are reinfected following clearance of a primary infection.⁵ While clearance of HCV infection has been associated with strong and broad T cell responses,[6], [7] little is known about the role of antibodies in spontaneous clearance of HCV infection and protection upon re-exposure.

HCV clearance has been associated with a neutralizing antibody response against HCV E1E2 glycoproteins during the early phase of infection.[8], [9] In addition, a number of broadly neutralizing antibodies have been isolated from B cells of chronically infected individuals. In general, they target 1 of 3 epitopes which are located in or around the CD81 binding site: epitope I (amino acids 412–423), epitope II (amino acids 434–446) and domain B (amino acids 523–535).[10], [11], [12] Interestingly, broadly neutralizing antibodies targeting epitope I or epitope II (AP33, HC84.26) protected humanized mice against HCV genotype 1b infection.[13], [14] It has also been shown that AR3A and AR3B antibodies targeting both epitope II and domain B, jointly referred to as antigenic region 3 (AR3), protected mice against HCV infection from isolate H77 (genotype 1a) and isolate J6 (genotype 2a) in combination with AR4A, an antibody recognizing antigenic region 4 (AR4).[15], [16], [17] However, whether such broadly neutralizing antibodies contribute to spontaneous clearance and long-term immune protection in humans with ongoing exposure remains unanswered.

The Amsterdam Cohort Study (ACS) among drug users (DU), is a prospective cohort study investigating human immunodeficiency virus (HIV) and HCV infections, in which serum, peripheral blood mononuclear cells (PBMCs), and socio-demographic and risk behavioural data are collected regularly.¹⁸ The ACS-DU cohort started in 1985 and came to an end in 2016, making it a unique cohort with one of the longest follow-up periods recorded in DUs globally.¹⁹ Importantly, all ACS participants who are injecting drug users (IDU) are, most likely, frequently (re-)exposed to HCV, since 65% reported at least weekly injecting drug use at enrolment in the cohort, with a baseline HCV antibody prevalence of 82% and an incidence of up to 28 primary infections per 100 person-years among IDU.²⁰ Such a well-characterized cohort of highly exposed individuals with a long follow-up presents a unique opportunity to study the role of broadly neutralizing antibodies in the spontaneous clearance of HCV infection and protection upon re-exposure.

Herein, we studied the frequency, cross-reactivity and epitopes of HCV E1E2 specific antibodies produced by memory B cells from ACS participants. We found that the frequency of HCV specific cross-genotype antibodies, targeting mainly AR3 and AR4, was associated with spontaneous clearance of ≥1 HCV infection(s) and absence of HCV RNA at the end of the study period.

Section snippets

Participants

Individuals were selected from the ACS-IDU. After giving written informed consent, ACS participants visited the Amsterdam Health Service every 4 to 6 months, where blood was drawn for laboratory testing, PBMCs were stored and participants completed a standardized questionnaire on risk behaviour.¹⁸ Our study relies in part on self-reports, which have been shown to be a valid method for measuring behavioural variables in our cohort, where social desirability does not play an important role.²¹

For

Characteristics of the study population

Thirteen cohort participants with acute or recent HCV infection met the inclusion criteria for this study. The median age of the selected individuals was 29 years (interquartile range [IQR] 23–33) at the time of HCV infection (Table 1). The median follow-up time of these individuals after primary HCV infection was 17.5 years (IQR 11.7–18.9). The individuals were classified into 2 groups based on the outcome of HCV infection: (i) individuals who became chronically infected (CHRs; n = 5) either

Discussion

For the design of a protective HCV vaccine, a detailed understanding of the mechanism by which HCV infection is spontaneously cleared, is crucial. A strong and broad T cell response has been associated with clearance of HCV (re)infection.[6], [7] However, the role of B cells producing HCV neutralizing antibody is largely undefined. Here, we studied the B cell repertoire against HCV E1E2 in a cohort of persistent IDU following clearance of primary HCV infection. We compared the breadth of the

Financial support

This study was supported by the Virgo consortium, funded by the Dutch government, project number FES0908 and by the Netherlands Genomics Initiative (NGI) project number 050-060-452. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.

Conflicts of interest

S.J.M, C.B., D.V.B., A.Q.B., H.S. and T.B. are employees of AIMM Therapeutics and S.J.M, A.Q.B., H.S. and T.B. shareholders of AIMM Therapeutics. M.D.J. was a member of the AIMM scientific advisory board.

Please refer to the accompanying ICMJE disclosure forms for further details.

Authors’ contributions

Study concept and design: Sabrina J. Merat, Menno D. de Jong, Hergen Spits, Tim Beaumont and Janke Schinkel. Study supervision: Sabrina J. Merat, Richard Molenkamp, Jonathan K. Ball, Tim Beaumont and Janke Schinkel. Funding acquisition: Jonathan K. Ball, Menno D. de Jong, Hergen Spits, Tim Beaumont and Janke Schinkel. Amsterdam Cohort Project lead and supervision: Maria Prins, Neeltje Kootstra. Acquisition of the data: Sabrina J. Merat, Camille Bru, Dorien van de Berg, Richard Molenkamp, Arjen

Acknowledgements

We would like to thank the cohort participants of the Amsterdam Cohort Studies, Margreet Bakker for the data management, Agnes Harskamp – Holwerda for sample storage and handling and all doctors and nurses of the Amsterdam Cohort Studies for data collection and blood sampling. The Amsterdam Cohort Studies on HIV infection and AIDS, a collaboration between the Amsterdam Municipal Health Service, the Academic Medical Center of the University of Amsterdam, Sanquin Blood Supply Foundation, and the

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^†: Camille Bru and Dorien van de Berg contributed equally to this work.

^‡: Tim Beaumont and Janke Schinkel contributed equally as senior authors.

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Research ArticleCross-genotype AR3-specific neutralizing antibodies confer long-term protection in injecting drug users after HCV clearance

Highlights

Background & Aims

Methods

Results

Conclusions

Lay summary

Graphical abstract

Introduction

Section snippets

Participants

Characteristics of the study population

Discussion

Financial support

Conflicts of interest

Authors’ contributions

Acknowledgements

J Hepat

Lancet Infect Dis

Estimating HCV disease burden-volume 4 (editorial)

J Viral Hepat

Hepatitis C virus reinfection and spontaneous clearance of reinfection-the InC3 Study

J Infect Dis

Broad repertoire of the CD4+ Th cell response in spontaneously controlled hepatitis C virus infection includes dominant and highly promiscuous epitopes

J Immunol

Signatures of protective memory immune responses during hepatitis C virus reinfection

Gastroenterology

Rapid induction of virus-neutralizing antibodies and viral clearance in a single-source outbreak of hepatitis C

Proc Natl Acad Sci U S A

Clearance of hepatitis C infection is associated with the early appearance of broad neutralizing antibody responses

Hepatology

Monoclonal antibody AP33 defines a broadly neutralizing epitope on the hepatitis C virus E2 envelope glycoprotein

J Virol

Hepatitis C virus epitope-specific neutralizing antibodies in Igs prepared from human plasma

Proc Natl Acad Sci U S A

Hepatitis C virus E2 has three immunogenic domains containing conformational epitopes with distinct properties and biological functions

J Virol

Monoclonal anti-envelope antibody AP33 protects humanized mice against a patient-derived hepatitis C virus challenge

Hepatology

Affinity maturation of a broadly neutralizing human monoclonal antibody that prevents acute HCV infection

Hepatology

Broadly neutralizing antibodies protect against hepatitis C virus quasispecies challenge

Nat Med

Human broadly neutralizing antibodies to the envelope glycoprotein complex of hepatitis C virus

Proc Natl Acad Sci U S A

Broadly neutralizing antibodies abrogate established hepatitis C virus infection

Sci Transl Med

Prevalence and risk factors of HIV infections among drug users and drug-using prostitutes in Amsterdam

Aids

Cohort profile: the international collaboration of incident HIV and hepatitis C in injecting cohorts (InC3) study

Int J Epidemiol

Research Article
Cross-genotype AR3-specific neutralizing antibodies confer long-term protection in injecting drug users after HCV clearance