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

Merat, Sabrina J.; Bru, Camille; van de Berg, Dorien; Molenkamp, Richard; Tarr, Alexander W.; Koekkoek, Sylvie; Kootstra, Neeltje A.; Prins, Maria; Ball, Jonathan K.; Bakker, Arjen Q.; de Jong, Menno D.; Spits, Hergen; Beaumont, Tim; Schinkel, Janke

Abstract

Background & Aims
Understanding immune protection against hepatitis C virus (HCV) infection is necessary for designing an effective vaccine. A number of broadly-reactive, neutralizing antibodies have been isolated from B cells of HCV-infected subjects. However, it remains unclear whether B cells producing such antibodies contribute to the clearance and long-term immune protection against HCV.

Methods
We analysed the B-cell repertoire of thirteen participants from the Amsterdam Cohort Study among injecting drug users with a median follow-up of 17.5 years. Five subjects ultimately became chronically infected either after primary infection or after reinfection. Eight subjects, at the end of study follow-up, were HCV RNA negative following spontaneous clearance of one or multiple infections. From each subject, 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 one or multiple infections (p-value=0.03). Epitope specificity of these cross-genotype antibodies was determined by alanine mutant scanning in four subjects, who were HCV RNA negative following spontaneous clearance of one or multiple infections. Interestingly, the cross-genotype antibodies were mainly AR3-specific and showed cross-neutralizing activity against HCV. In addition to AR3 antibodies, three subjects developed antibodies recognizing AR4 of which one 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, contribute to HCV clearance and long-term immune protection against HCV.

Citation

Merat, S. J., Bru, C., van de Berg, D., Molenkamp, R., Tarr, A. W., Koekkoek, S., Kootstra, N. A., Prins, M., Ball, J. K., Bakker, A. Q., de Jong, M. D., Spits, H., Beaumont, T., & Schinkel, J. (2019). Cross-genotype AR3-specific neutralizing antibodies confer long-term protection in injecting drug users after HCV clearance. Journal of Hepatology, 71(1), 14-24. https://doi.org/10.1016/j.jhep.2019.02.013

• Journal Article Type: Article
• Acceptance Date: Feb 12, 2019
• Online Publication Date: Feb 21, 2019
• Publication Date: Jul 1, 2019
• Deposit Date: Mar 20, 2019
• Publicly Available Date: Mar 20, 2019
• Journal: Journal of Hepatology
• Print ISSN: 0168-8278
• Electronic ISSN: 1600-0641
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 71
• Issue: 1
• Pages: 14-24
• DOI: https://doi.org/10.1016/j.jhep.2019.02.013
• Keywords: Injecting drug user; HCV infection; Spontaneous clearance; Memory B cell; Broadly neutralizing antibody
• Public URL: https://nottingham-repository.worktribe.com/output/1661570
• Publisher URL: https://www.sciencedirect.com/science/article/pii/S016882781930128X?via%3Dihub
• Contract Date: Mar 20, 2019