P656 THE ROLE OF SEQUENCE VARIATION IN T-CELL EPITOPES OF THE HEPATITIS B VIRUS (HBV) POLYMERASE AND ENVELOPE PROTEINS IN HBeAg CLEARANCE AND DISEASE PROGRESSION

ABSTRACT Immunotherapy represents an attractive option for the treatment of chronic hepatitis B virus (HBV) infection. The HBV proteins polymerase (Pol) and HBx are of special interest for antigen-specific immunotherapy because they are essential for viral replication and have been associated with viral control (Pol) or are still expressed upon viral DNA integration (HBx). Here, we scored all currently described HBx- and Pol-derived epitope sequences for viral indispensability and conservation across all HBV genotypes. This yielded 7 HBx-derived and 26 Pol-derived reported epitopes with functional association and high conservation. We subsequently predicted novel HLA-binding peptides for 6 HLA supertypes prevalent in HBV-infected patients. Potential epitopes expected to be the least prone to immune escape were subjected to a state-of-the-art in vitro assay to validate their HLA-binding capacity. Using this method, a total of 13 HLA binders derived from HBx and 33 binders from Pol were identified across HLA types. Subsequently, we demonstrated interferon gamma (IFN-γ) production in response to 5 of the novel HBx-derived binders and 17 of the novel Pol-derived binders. In addition, we validated several infrequently described epitopes. Collectively, these results specify a set of highly potent T cell epitopes that represent a valuable resource for future HBV immunotherapy design. IMPORTANCE Multiple HBV-derived T cell epitopes have been reported, which can be useful in a therapeutic vaccination strategy. However, these epitopes are largely restricted to HLA-A*02, which is not dominantly expressed in populations with high HBV prevalence. Thus, current epitopes are falling short in the development of a global immunotherapeutic approach. Therefore, we aimed to identify novel epitopes for 6 HLA supertypes most prevalent in the infected population. Moreover, established epitopes might not all be equally effective as they can be subject to different levels of immune escape. It is therefore important to identify targets that are crucial in viral replication and conserved in the majority of the infected population. Here, we applied a stringent selection procedure to compose a combined overview of existing and novel HBV-derived T cell epitopes most promising for viral eradication. This set of T cell epitopes now lays the basis for the development of globally effective HBV antigen-specific immunotherapies.

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4818527 T cell epitopes of the hepatitis B virus nucleocapsid protein

Biotechnology Advances ◽

10.1016/0734-9750(89)90289-9 ◽

1989 ◽

Vol 7 (3) ◽

pp. 446

Keyword(s):

Hepatitis B Virus ◽

T Cell ◽

Hepatitis B ◽

Nucleocapsid Protein ◽

T Cell Epitopes ◽

B Virus

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In vivo hierarchy of immunodominant and subdominant HLA-A*0201-restricted T-cell epitopes of HBx antigen of hepatitis B virus

Microbes and Infection ◽

10.1016/j.micinf.2004.12.022 ◽

2005 ◽

Vol 7 (4) ◽

pp. 626-634 ◽

Cited By ~ 9

Author(s):

Silvina Malmassari ◽

Yu Chun Lone ◽

Menghua Zhang ◽

Catherine Transy ◽

Marie-Louise Michel

Keyword(s):

Hepatitis B Virus ◽

T Cell ◽

Hepatitis B ◽

T Cell Epitopes ◽

B Virus

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Identification of immunodominant T cell epitopes of the hepatitis B virus nucleocapsid antigen.

Journal of Clinical Investigation ◽

10.1172/jci115280 ◽

1991 ◽

Vol 88 (1) ◽

pp. 214-222 ◽

Cited By ~ 160

Author(s):

C Ferrari ◽

A Bertoletti ◽

A Penna ◽

A Cavalli ◽

A Valli ◽

...

Keyword(s):

Hepatitis B Virus ◽

T Cell ◽

Hepatitis B ◽

T Cell Epitopes ◽

B Virus

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Mutations of T-Cell Epitopes in the Hepatitis B Virus Surface Gene in Children With Chronic Infection and Hepatocellular Carcinoma

The American Journal of Gastroenterology ◽

10.1111/j.1572-0241.2007.01727.x ◽

2008 ◽

Vol 103 (4) ◽

pp. 1004-1009 ◽

Cited By ~ 4

Author(s):

Yen-Hsuan Ni ◽

Mei-Hwei Chang ◽

Hong-Yuan Hsu ◽

Yi-Ching Tung ◽

Huey-Ling Chen ◽

...

Keyword(s):

Hepatocellular Carcinoma ◽

Hepatitis B Virus ◽

T Cell ◽

Hepatitis B ◽

Chronic Infection ◽

T Cell Epitopes ◽

Virus Surface ◽

B Virus ◽

Surface Gene

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CD8+ T-Cell Response-Associated Evolution of Hepatitis B Virus Core Protein and Disease Progress

Journal of Virology ◽

10.1128/jvi.02120-17 ◽

2018 ◽

Vol 92 (17) ◽

Cited By ~ 4

Author(s):

Yu Zhang ◽

Yan Wu ◽

Mengmeng Deng ◽

Dongping Xu ◽

Xiaodong Li ◽

...

Keyword(s):

T Cell ◽

Hepatitis B ◽

Disease Progression ◽

Core Protein ◽

T Cell Response ◽

Clinical Parameters ◽

T Cell Epitopes ◽

Terminal Portion ◽

Immune Pressure ◽

B Virus

ABSTRACT Under the immune pressure of cytotoxic T cells (CTLs), hepatitis B virus (HBV) evolves to accumulate mutations more likely within epitopes to evade immune detection. However, little is known about the specific patterns of the immune pressure-associated HBV mutation of T-cell epitopes and their link to disease progression. Here, we observed a correlation of the accumulated variants on HBV core protein (HBc) with the disease severity of HBV infection. Further analysis indicated that these substitutions were mostly located within CD8+ T-cell epitopes of HBc protein, which were systematically screened and identified in an unbiased manner in our study. From individual peptide level to the human leukocyte antigen I (HLA-I)-restricted population level, we elucidated that the mutations in these well-defined HLA-I-restricted T-cell epitopes significantly decreased antiviral activity-specific CTLs and were positively associated with clinical parameters and disease progression in HBV-infected patients. The molecular pattern for viral epitope variations based on the sequencing of 105 HBV virus genomes indicated that the C-terminal portion (Pc), especially the Pc-1 and Pc-2 positions, have the highest mutation rates. Further structural analysis of HLA-A*02 complexed to diverse CD8+ T-cell epitopes revealed that the highly variable C-terminal bulged peak of M-shaped HBc-derived epitopes are solvent exposed, and most of the CDR3βs of the T-cell receptor hover over them. These data shed light on the molecular and immunological mechanisms of T-cell immunity-associated viral evolution in hepatitis B progression, which is beneficial for designing immunotherapies and vaccines. IMPORTANCE The specific patterns of sequence polymorphisms of T-cell epitopes and the immune mechanisms of the HBV epitope mutation-linked disease progression are largely unclear. In this study, we systematically evaluated the contribution of CD8+ T cells to the disease progress-associated evolution of HBV. By evaluation of patient T-cell responses based on the peptide repertoire, we comprehensively characterized the association of clinical parameters in chronic hepatitis B with the antiviral T-cell response-associated mutations of the viruses from the single-epitope level to the overall HLA-I-restricted peptide levels. Furthermore, we investigated the molecular basis of the HLA-A2-restricted peptide immune escape and found that the solvent-exposed C-terminal portion of the epitopes is highly variable under CDR3β recognition. Our work may provide a comprehensive evaluation of viral mutations impacted by the host CTL response in HBV disease progression in the context of the full repertoire of HBc-derived epitopes.

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Hepatitis B virus polymerase-specific T cell epitopes shift in a mouse model of chronic infection

Virology Journal ◽

10.1186/s12985-021-01712-y ◽

2021 ◽

Vol 18 (1) ◽

Author(s):

Mohadeseh Hasanpourghadi ◽

Mikhail Novikov ◽

Dakota Newman ◽

ZhiQuan Xiang ◽

Xiang Yang Zhou ◽

...

Keyword(s):

Hepatitis B Virus ◽

T Cell ◽

Hepatitis B ◽

Checkpoint Inhibitor ◽

Public Health Problem ◽

T Cell Responses ◽

T Cell Epitopes ◽

Cell Responses ◽

Chronic Hepatitis B Virus ◽

B Virus

Abstract Background Chronic hepatitis B virus (HBV) infection (CHB) is a significant public health problem that could benefit from treatment with immunomodulators. Here we describe a set of therapeutic HBV vaccines that target the internal viral proteins. Methods Vaccines are delivered by chimpanzee adenovirus vectors (AdC) of serotype 6 (AdC6) and 7 (AdC7) used in prime only or prime-boost regimens. The HBV antigens are fused into an early T cell checkpoint inhibitor, herpes simplex virus (HSV) glycoprotein D (gD), which enhances and broadens vaccine-induced cluster of differentiation (CD8)+ T cell responses. Results Our results show that the vaccines are immunogenic in mice. They induce potent CD8+ T cell responses that recognize multiple epitopes. CD8+ T cell responses increase after a boost, although the breadth remains similar. In mice, which carry high sustained loads of HBV particles due to a hepatic infection with an adeno-associated virus (AAV)8 vector expressing the 1.3HBV genome, CD8+ T cell responses to the vaccines are attenuated with a marked shift in the CD8+ T cells’ epitope recognition profile. Conclusions Our data show that in different stains of mice including those that carry a human major histocompatibility complex (MHC) class I antigen HBV vaccines adjuvanted with a checkpoint inhibitor induce potent and broad HBV-specific CD8+ T cell responses and lower but still detectable CD4+ T cell responses. CD8+ T cell responses are reduced and their epitope specificity changes in mice that are chronically exposed to HBV antigens. Implications for the design of therapeutic HBV vaccines are discussed.

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Role for Calnexin and N-Linked Glycosylation in the Assembly and Secretion of Hepatitis B Virus Middle Envelope Protein Particles

Journal of Virology ◽

10.1128/jvi.72.1.778-782.1998 ◽

1998 ◽

Vol 72 (1) ◽

pp. 778-782 ◽

Cited By ~ 51

Author(s):

Margaret Werr ◽

Reinhild Prange

Keyword(s):

Hepatitis B Virus ◽

Hepatitis B ◽

Envelope Proteins ◽

Particle Release ◽

B Virus ◽

Middle Envelope ◽

Protein Particles ◽

Specific Association ◽

Subviral Particle

ABSTRACT Unlike those of the S and the L envelope proteins, the functional role of the related M protein in the life cycle of the hepatitis B virus (HBV) is less understood. We now demonstrate that a single N glycan, specific for M, is required for efficient secretion of M empty envelope particles. Moreover, this glycan mediates specific association of M with the chaperone calnexin. Conversely, the N glycan, common to all three envelope proteins, is involved neither in calnexin binding nor in subviral particle release. As proper folding and trafficking of M need the assistance of the chaperone, the glycan-dependent association of M with calnexin may thus play a crucial role in the assembly of HBV. Beyond being modified by N glycosylation, M is modified by O glycosylation occurring within its amino acid sequence at positions 27 to 47. The O glycans, however, were found to be dispensable for secretion of M but may rather support viral infectivity. Surprisingly, nonglycosylated M localizes exclusively to the cytosol, either for degradation or for a yet-unknown function.

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