The L60V Variation in Hepatitis B Virus Core Protein Elicits New Epitope-Specific Cytotoxic T Lymphocytes and Enhances Viral Replication

Abstract

Mutations in the core protein (HBc) of hepatitis B virus (HBV) are associated with aggressive hepatitis and advanced liver diseases in chronic hepatitis B (CHB). In this study, we identified the L60V variation in HBc that generates a new HLA-A2-restricted CD8 ؉ T cell epitope by screening an overlapping 9-mer peptide pool covering HBc and its variants. The nonameric epitope V60 was determined by structural and immunogenic analysis. The HBc L60V variation is correlated with hepatic necroinflammation and higher viral levels, and it may be associated with a poor prognosis in CHB patients. Immunization with the defined HBV epitope V60 peptide elicited specific cytotoxic T lymphocyte (CTL)-induced liver injury in HLA-A2 ؉ HBV transgenic mice. In addition, in vitro and in vivo experiments both demonstrated that the HBc L60V variation facilitates viral capsid assembly and increases HBV replication. These data suggest that the HBc L60V variation can impact both HBV replication and HBV-specific T cell responses. Therefore, our work provides further dissection of the impact of the HBc L60V variation, which orchestrates HBV replication, viral persistence, and immunopathogenesis during chronic viral infection. H epatitis B virus (HBV) is a strictly hepatotropic DNA virusaffecting about 350 million people worldwide, especially in Asia. Because HBV is not directly cytopathic, the liver damage induced by chronic hepatitis B (CHB) is thought to be mainly immune mediated. Hepatic infiltration of HBV-specific and nonspecific T cells, NK/NKT cells (1), dendritic cell subsets (2), macrophages (3), polymorphonuclear neutrophils (4), regulatory T cells (5), and intrahepatic Th17 cells (6) contributes to immunemediated liver pathogenesis and disease progression. Additionally, inflammatory cytokines (7), extracellular matrix proteins (8), chemokines (9), and platelets (10) are important in the complex interplay that orchestrates immune defects and immunopathogenesis during chronic viral infection. Of note, either by direct killing effects or by indirect inflammation-inducible behaviors, virus-specific cytotoxic T lymphocytes (CTLs) play a critical pathogenic role in HBV infection (3,11,12).As a highly prevalent hepadnavirus, HBV can evolve by mutations to increase its adaptation against environmental selection, and these mutations manifest as various effects on viral replication, clinical features, and the pathogenesis of HBV infection. The treatment of CHB with peginterferon and nucleotide analogues (e.g., lamivudine) causes a high risk of selecting for drug-resistant mutants, which primarily occur in association with a high rate of mutation in the basal core promoter and precore (BCP/pre-C) regions, as well as the reverse transcriptase (RT) domain, of the HBV genome (13-15). Mutations in the BCP/pre-C and RT regions are associated with aggressive hepatitis and advanced liver diseases, including severe and fulminant hepatitis B, cirrhosis, and hepatocellular carcinoma (HCC) (16-18). Because T cell responses play a critical role in con...

An Association Between Core Mutations in Hepatitis B Virus Genotype F1b and Hepatocellular Carcinoma in Alaskan Native People

“…and ; Supporting Fig. S3) . We also showed that the HCC‐associated mutant BCP/PC/2051 triggered inflammation and fibrosis in the human hepatocyte chimeric mouse model related to increased levels of genes that have been associated with HCC and/or cell proliferation.…”

Multi-omics analyses reveal metabolic alterations regulated by hepatitis B virus core protein in hepatocellular carcinoma cells

“…HBx, HBs and HBc could integrate with human genes to influence patient survival3940. In addition, hot spot mutations in HBc (L60V, S87G and I97L) can affect HBV replication, viral persistence, and immunopathogenesis during chronic viral infection4142. Thus, we are preparing to integrate the genomics data and transcriptomics data to study the role of HBc in the HBV-HCC.…”

Clinical Implications of Evolutionary Patterns of Homologous, Full-Length Hepatitis B Virus Quasispecies in Different Hosts after Perinatal Infection

“…Second, the preC/C region is abundant with epitopes of both B cells and T cells, which are critical for host immunity to clear virus (24,27); mutations in this region are associated with advanced liver diseases, including severe and fulminant hepatitis B, cirrhosis, and hepatocellular car- (22) cinoma (33)(34)(35). HBV could evolve by mutations and indels to increase its adaptation against environmental selection, and these mutations manifest as escaping from host immunity to survival or lowering the binding affinity of epitopes to lymphocytes (36). Nucleotide substitution rates or evolution rates of full-length HBV were 7.9 ϫ 10 Ϫ5 substitutions/site/year as reported by Osiowy et al (37), which was slightly higher than previously published estimates (1.5 ϫ 10 Ϫ5 to 5 ϫ 10 Ϫ5 substitutions/site/year) (38)(39)(40).…”