B-cell characteristics define HCV reinfection outcome

• Published in: Journal of hepatology Vol. 81; no. 3; pp. 415 - 428
• Main Authors: Underwood, Alexander P., Gupta, Money, Wu, Bing-Ru, Eltahla, Auda A., Boo, Irene, Wang, Jing Jing, Agapiou, David, Abayasingam, Arunasingam, Reynaldi, Arnold, Keoshkerian, Elizabeth, Zhao, Yanran, Brasher, Nicholas, Walker, Melanie R., Bukh, Jens, Maher, Lisa, Gordon, Tom, Davenport, Miles P., Luciani, Fabio, Drummer, Heidi E., Lloyd, Andrew R., Bull, Rowena A.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.09.2024
• Subjects: Adult; Antibodies, Neutralizing - blood; Antibodies, Neutralizing - immunology; B cell; B-Lymphocytes - immunology; clearance; Female; HCV; Hepacivirus - genetics; Hepacivirus - immunology; Hepatitis C - immunology; Hepatitis C Antibodies - blood; Hepatitis C Antibodies - immunology; Humans; Male; Memory B Cells - immunology; Middle Aged; neutralising antibody; persistence; reinfection; Reinfection - immunology; B cell; clearance; persistence; reinfection; HCV; neutralising antibody
• ISSN: 0168-8278; 1600-0641; 1600-0641
• DOI: 10.1016/j.jhep.2024.04.004

In individuals highly exposed to HCV, reinfection is common, suggesting that natural development of sterilising immunity is difficult. In those that are reinfected, some will develop a persistent infection, while a small proportion repeatedly clear the virus, suggesting natural protection is possible. The aim of this study was to characterise immune responses associated with rapid natural clearance of HCV reinfection. Broad neutralising antibodies (nAbs) and Envelope 2 (E2)-specific memory B cell (MBC) responses were examined longitudinally in 15 individuals with varied reinfection outcomes. Broad nAb responses were associated with MBC recall, but not with clearance of reinfection. Strong evidence of antigen imprinting was found, and the B-cell receptor repertoire showed a high level of clonality with ongoing somatic hypermutation of many clones over subsequent reinfection events. Single-cell transcriptomic analyses showed that cleared reinfections featured an activated transcriptomic profile in HCV-specific B cells that rapidly expanded upon reinfection. MBC quality, but not necessarily breadth of nAb responses, is important for protection against antigenically diverse variants, which is encouraging for HCV vaccine development. HCV continues to have a major health burden globally. Limitations in the health infrastructure for diagnosis and treatment, as well as high rates of reinfection, indicate that a vaccine that can protect against chronic HCV infection will greatly complement current efforts to eliminate HCV-related disease. With alternative approaches to testing vaccines, such as controlled human inoculation trials under consideration, we desperately need to identify the correlates of immune protection. In this study, in a small but rare cohort of high-risk injecting drug users who were reinfected multiple times, breadth of neutralisation was not associated with ultimate clearance of the reinfection event. Alternatively, characteristics of the HCV-specific B-cell response associated with B-cell proliferation were. This study indicates that humoral responses are important for protection and suggests that for genetically very diverse viruses, such as HCV, it may be beneficial to look beyond just antibodies as correlates of protection. [Display omitted] •Protection from persistent reinfection was associated with expansion of E2-specific B cells upon reinfection.•E2-specific B cells have a transcriptomic profile associated with activation and proliferation prior to clearance of reinfection.•We observed evidence of antigen imprinting in HCV reinfection.