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Zhang J, Wang Q, Yuan W, Li J, Yuan Q, Zhang J, Xia N, Wang Y, Li J, Tong S. Both middle and large envelope proteins can mediate neutralization of hepatitis B virus infectivity by anti-preS2 antibodies: escape by naturally occurring preS2 deletions. J Virol 2024; 98:e0192923. [PMID: 39078152 PMCID: PMC11334434 DOI: 10.1128/jvi.01929-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2023] [Accepted: 07/02/2024] [Indexed: 07/31/2024] Open
Abstract
Hepatitis B virus (HBV) expresses co-terminal large (L), middle (M), and small (S) envelope proteins containing preS1/preS2/S, preS2/S, and S domain alone, respectively. S and preS1 domains mediate sequential virion attachment to heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP), respectively, which can be blocked by anti-S and anti-preS1 antibodies. How anti-preS2 antibodies neutralize HBV infectivity remains enigmatic. The late stage of chronic HBV infection often selects for mutated preS2 translation initiation codon to prevent M protein expression, or in-frame preS2 deletions to shorten both L and M proteins. When introduced to infectious clone of genotype C or D, both M-minus mutations and most 5' preS2 deletions sustained virion production. Such mutant progeny viral particles were infectious in NTCP-reconstituted HepG2 cells. Neutralization experiments were performed on the genotype D clone. Although remaining susceptible to anti-preS1 and anti-S neutralizing antibodies, M-minus mutants were only partially neutralized by two anti-preS2 antibodies tested while preS2 deletion mutants were resistant. By infection experiments using viral particles with lost versus increased M protein expression, or a neutralization escaping preS2 deletion only present on L or M protein, we found that both full-length L and M proteins contributed to virus neutralization by the two anti-preS2 antibodies. Thus, immune escape could be a driving force for the selection of M-minus mutations, and especially preS2 deletions. The fact that both L and M proteins could mediate neutralization by anti-preS2 antibodies may shed light on the underlying molecular mechanism.IMPORTANCEThe large (L), middle (M), and small (S) envelope proteins of hepatitis B virus (HBV) contain preS1/preS2/S, preS2/S, and S domain alone, respectively. The discovery of heparan sulfate proteoglycans and sodium taurocholate cotransporting polypeptide (NTCP) as the low- and high-affinity HBV receptors could explain neutralizing potential of anti-S and anti-preS1 antibodies, respectively, but how anti-preS2 neutralizing antibodies work remains enigmatic. In this study, we found two M-minus mutants in the context of genotype D partially escaped two anti-preS2 neutralizing antibodies in NTCP-reconstituted HepG2 cells, while several naturally occurring preS2 deletion mutants escaped both antibodies. By point mutations to eliminate or enhance M protein expression, and by introducing preS2 deletion selectively to L or M protein, we found binding of anti-preS2 antibodies to both L and M proteins contributed to neutralization of wild-type HBV infectivity. Our finding may shed light on the possible mechanism(s) whereby anti-preS2 antibodies neutralize HBV infectivity.
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Affiliation(s)
- Jing Zhang
- Department of Pathobiology, Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Qianru Wang
- Department of Pathobiology, Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Wenqing Yuan
- Liver Research Center, Rhode Island Hospital, The Warren Alpert School of Medicine, Brown University, Providence, Rhode Island, USA
| | - Jing Li
- Liver Research Center, Rhode Island Hospital, The Warren Alpert School of Medicine, Brown University, Providence, Rhode Island, USA
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Quan Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Jiming Zhang
- Department of Infectious Diseases, Huashan Hospital, Fudan University, Shanghai, China
| | - Ningshao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Public Health, Xiamen University, Xiamen, China
| | - Yongxiang Wang
- Department of Pathobiology, Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
| | - Jisu Li
- Liver Research Center, Rhode Island Hospital, The Warren Alpert School of Medicine, Brown University, Providence, Rhode Island, USA
| | - Shuping Tong
- Department of Pathobiology, Key Laboratory of Medical Molecular Virology, School of Basic Medical Sciences, Fudan University, Shanghai, China
- Liver Research Center, Rhode Island Hospital, The Warren Alpert School of Medicine, Brown University, Providence, Rhode Island, USA
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Parizad EG, Imani Fooladi AA, Sedighian H, Behzadi E, Amani J, Khosravi A. Immune response induced by recombinant pres2/S-protein and a pres2-S-protein fused with a core 18-27 antigen fragment of hepatitis B virus compared to conventional HBV vaccine. Virus Genes 2023:10.1007/s11262-023-01995-z. [PMID: 37140777 DOI: 10.1007/s11262-023-01995-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/07/2023] [Indexed: 05/05/2023]
Abstract
Although comprehensive vaccination is the cornerstone of public health programs to control hepatitis B virus (HBV) infections, 5% of people who receive the existing vaccine do not develop proper immunity against HBV. To overcome this challenge, researchers have tried using various protein fragments encoded by the virus genome to achieve better immunization rates. An important antigenic component of HBsAg called the preS2/S or M protein has also received much attention in this area. The gene sequences of preS2/S and Core18-27 peptide were extracted from the GenBank (NCBI). Final gene synthesis was conducted with pET28. Groups of BALB/c mice were immunized with 10 μg/ml of recombinant proteins and 1 μg/ml CPG7909 adjuvant. Serum levels of IF-γ, TNF-α, IL-2, IL-4, and IL-10 were measured by ELISA assay method on spleen cell cultures on day 45, and IgG1, IgG2a, and total IgG titers obtained from mice serum were quantified on days 14 and 45. Statistical analysis did not show any significant difference between the groups regarding IF-γ level. There were, however, significant differences in terms of IL-2 and IL-4 levels between the groups receiving preS2/S-C18-27 with and without adjuvant and the groups receiving both preS2/S and preS2/S-C18-27 (Plus Recomb-Plus Recomb: the group of mice that received both preS2/S and preS2/S-C18-27 simultaneously). The strongest total antibody production was induced by immunization with both recombinant proteins without CPG adjuvant. The groups that received both preS2/S and preS2/S-C18-27, whether with or without adjuvant, were significantly different from those that received the conventional vaccine considering most abundant interleukins. This difference suggested that higher levels of efficacy can be achieved by the use of multiple virus antigen fragments rather than using a single fragment.
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Affiliation(s)
| | - Abbas Ali Imani Fooladi
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Vanak Sq. Mollasadra St., P.O. Box 19395-5487, Tehran, Iran.
| | - Hamid Sedighian
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Vanak Sq. Mollasadra St., P.O. Box 19395-5487, Tehran, Iran
| | - Elham Behzadi
- Academy of Medical Sciences of the I.R. of Iran, Tehran, Iran
| | - Jafar Amani
- Applied Microbiology Research Center, Systems Biology and Poisonings Institute, Baqiyatallah University of Medical Sciences, Vanak Sq. Mollasadra St., P.O. Box 19395-5487, Tehran, Iran
| | - Afra Khosravi
- Clinical Microbiology Research Center, Ilam University of Medical Sciences, Ilam, Iran.
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Beretta M, Mouquet H. Advances in human monoclonal antibody therapy for HBV infection. Curr Opin Virol 2022; 53:101205. [PMID: 35123237 DOI: 10.1016/j.coviro.2022.101205] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2021] [Revised: 12/10/2021] [Accepted: 01/15/2022] [Indexed: 12/17/2022]
Abstract
HBV neutralizing antibodies target the viral envelope antigens (HBsAg) and confer long-term immune protection in vaccinees and infected humans who seroconvert. They recognize various HBsAg epitopes, and can be armed with Fc-dependent effector functions essential for eliminating infected cells and stimulating adaptive immunity. Hundreds of HBsAg-specific monoclonal antibodies (mAbs) were produced from the early 80's, but it is only recently that bona fide human anti-HBV mAbs were generated from vaccinees and seroconverters. Neutralizing HBV mAbs have in vivo prophylactic and therapeutic efficacy in animal models, and the capacity to decrease antigenemia and viremia in infected humans. Thus, polyfunctional, potent and broad human HBV neutralizing mAbs offer novel opportunities to develop effective interventions to prevent and treat HBV infection. Here, we summarize recent findings on the humoral immune response to HBV, and explore the potential of human HBV neutralizing mAbs as immunotherapeutics to help achieving a functional cure for HBV.
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Affiliation(s)
- Maxime Beretta
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, 75015, France; INSERM U1222, Paris, 75015, France
| | - Hugo Mouquet
- Laboratory of Humoral Immunology, Department of Immunology, Institut Pasteur, Paris, 75015, France; INSERM U1222, Paris, 75015, France.
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5' preS1 mutations to prevent large envelope protein expression from hepatitis B virus genotype A or genotype D markedly increase polymerase-envelope fusion protein. J Virol 2022; 96:e0172321. [PMID: 35019714 PMCID: PMC8906437 DOI: 10.1128/jvi.01723-21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Hepatitis B virus (HBV) large (L) envelope protein is translated from 2.4-kb RNA. It contains preS1, preS2, and S domains and is detected in Western blot as p39 and gp42. The 3.5-kb pregenomic RNA produces core and polymerase (P) proteins. We generated L-minus mutants of a genotype A clone and a genotype D clone from 1.1mer or 1.3mer construct, with the former overproducing pregenomic RNA. Surprisingly, mutating preS1 ATG codon(s) or introducing a nonsense mutation soon afterwards switched secreted p39/gp42 into p41/p44 doublet, with its amount further increased by a nonsense mutation in the core gene. A more downstream preS1 nonsense mutation prevented p41/p44 production. Tunicamycin treatment confirmed p44 as glycosylated form of p41. In this regard splicing of 3.5-kb RNA to generate nt2447-nt2902 junction for genotype D enables translation of p43, with N-terminal 47 residues of P protein fused to C-terminal 371 residues of L protein. Indeed p41/p44 were detectable by an antibody against N-terminus of P protein, and eliminated by a nonsense mutation at 5' P gene or a point mutation to prevent that splicing. Therefore, lost L (and core) protein expression from 1.1mer or 1.3mer construct markedly increased p41/p44 (p43), the P-L fusion protein. Co-transfection with an expression construct for L/M proteins reversed high extracellular p41/p44 associated with L-minus mutants, suggesting that L protein retains p43 in wild-type HBV to promote its intracellular degradation. Considering that p43 lacks N-terminal preS1 sequence critical for receptor binding, its physiological significance during natural infection and therapeutic potential warrant further investigation. IMPORTANCE The large (L) envelope protein of hepatitis B virus (HBV) is translated from 2.4-kb RNA and detected in Western blot as p39 and gp42. Polymerase (P) protein is expressed at a low level from 3.5-kb RNA. The major spliced form of 3.5-kb RNA will produce a fusion protein between the first 47 residues of P protein and a short irrelevant sequence, although also at a low level. Another spliced form has the same P protein sequence fused to L protein missing its first 18 residues. We found that some point mutations to eliminate L and core protein expression from overlength HBV DNA constructs converted p39/gp42 into p41/gp44, which turned out to be that P-L fusion protein. Thus, the P-L fusion protein can be expressed at extremely high level when L protein expression is prevented. The underlying mechanism and functional significance of this variant form of L protein warrant further investigation.
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Lost Small Envelope Protein Expression from Naturally Occurring PreS1 Deletion Mutants of Hepatitis B Virus Is Often Accompanied by Increased HBx and Core Protein Expression as Well as Genome Replication. J Virol 2021; 95:e0066021. [PMID: 33910956 PMCID: PMC8223946 DOI: 10.1128/jvi.00660-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Hepatitis B virus (HBV) transcribes coterminal mRNAs of 0.7 to 3.5 kb from the 3.2-kb covalently closed circular DNA, with the 2.1-kb RNA being most abundant. The 0.7-kb RNA produces HBx protein, a transcriptional transactivator, while the 3.5-kb pregenomic RNA (pgRNA) drives core and P protein translation as well as genome replication. The large (L) and small (S) envelope proteins are translated from the 2.4-kb and 2.1-kb RNAs, respectively, with the majority of the S protein being secreted as noninfectious subviral particles and detected as hepatitis B surface antigen (HBsAg). pgRNA transcription could inhibit transcription of subgenomic RNAs. The present study characterized naturally occurring in-frame deletions in the 3' preS1 region, which not only codes for L protein but also serves as the promoter for 2.1-kb RNA. The human hepatoma cell line Huh7 was transiently transfected with subgenomic expression constructs for envelope (and HBx) proteins, dimeric constructs, or constructs mimicking covalently closed circular DNA. The results confirmed lost 2.1-kb RNA transcription and HBsAg production from many deletion mutants, accompanied by increases in other (especially 2.4-kb) RNAs, intracellular HBx and core proteins, and replicative DNA but impaired virion and L protein secretion. The highest intracellular L protein levels were achieved by mutants that had residual S protein expression or retained the matrix domain in L protein. Site-directed mutagenesis of a high replicating deletion mutant suggested that increased HBx protein expression and blocked virion secretion both contributed to the high replication phenotype. Our findings could help explain why such deletions are selected at a late stage of chronic HBV infection and how they contribute to viral pathogenesis. IMPORTANCE Expression of hepatitis B e antigen (HBeAg) and overproduction of HBsAg by wild-type HBV are implicated in the induction of immune tolerance to achieve chronic infection. How HBV survives the subsequent immune clearance phase remains incompletely understood. Our previous characterization of core promoter mutations to reduce HBeAg production revealed the ability of the 3.5-kb pgRNA to diminish transcription of coterminal RNAs of 2.4 kb, 2.1 kb, and 0.7 kb. The later stage of chronic HBV infection often selects for in-frame deletions in the preS region. Here, we found that many 3' preS1 deletions prevented transcription of the 2.1-kb RNA for HBsAg production, which was often accompanied by increases in intracellular 3.5-, 0.7-, and especially 2.4-kb RNAs, HBx and core proteins, and replicative DNA but lost virion secretion. These findings established the biological consequences of preS1 deletions, thus shedding light on why they are selected and how they contribute to hepatocarcinogenesis.
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Expression Level of Small Envelope Protein in Addition to Sequence Divergence inside Its Major Hydrophilic Region Contributes to More Efficient Surface Antigen Secretion by Hepatitis B Virus Subgenotype D2 than Subgenotype A2. Viruses 2020; 12:v12090967. [PMID: 32882910 PMCID: PMC7552069 DOI: 10.3390/v12090967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 08/28/2020] [Accepted: 08/30/2020] [Indexed: 02/08/2023] Open
Abstract
Hepatitis B surface antigen (HBsAg) promotes persistent hepatitis B virus (HBV) infection. It primarily corresponds to small (S) envelope protein secreted as subviral particles. We previously found that genotype D clones expressed less S protein than genotype A clones but showed higher extracellular/intracellular ratio of HBsAg suggesting more efficient secretion. The current study aimed to characterize the underlying mechanism(s) by comparing a subgenotype A2 clone (geno5.4) with a subgenotype D2 clone (geno1.2). Five types of full-length or subgenomic constructs were transfected to Huh7 cells at different dosage. HBsAg was quantified by enzyme linked immunosorbent assay while envelope proteins were detected by Western blot. We found that ratio of extracellular/intracellular HBsAg decreased at increasing amounts of DNA transfected. Conflicting findings from two types of subgenomic construct confirmed stronger secretion inhibitory effect of the genotype D-derived large envelope protein. Chimeric constructs followed by site-directed mutagenesis revealed geno1.2 specific V118/T127 and F161/A168 in the S protein as promoting and inhibitory of HBsAg secretion, respectively. In conclusion, more efficient HBsAg secretion by subgenotype D2 than subgenotype A2 is attributed to lower level of S protein expression in addition to V118 and T127 in S protein, although its F161 and A168 sequences rather reduce HBsAg secretion.
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Hong B, Wen Y, Ying T. Recent Progress on Neutralizing Antibodies against Hepatitis B Virus and its Implications. Infect Disord Drug Targets 2020; 19:213-223. [PMID: 29952267 DOI: 10.2174/1871526518666180628122400] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2017] [Revised: 05/13/2018] [Accepted: 06/22/2018] [Indexed: 01/22/2023]
Abstract
BACKGROUND Hepatitis B virus (HBV) infection remains a global health problem. As "cure" for chronic hepatitis B is of current priority, hepatitis B immunoglobulin (HBIG) has been utilized for several decades to provide post-exposure prophylaxis. In recent years, a number of monoclonal antibodies (mAbs) targeting HBV have been developed and demonstrated with high affinity, specificity, and neutralizing potency. OBJECTIVE HBV neutralizing antibodies may play a potentially significant role in the search for an HBV cure. In this review, we will summarize the recent progress in developing HBV-neutralizing antibodies, describing their characteristics and potential clinical applications. RESULTS AND CONCLUSION HBV neutralizing antibodies could be a promising alternative in the prevention and treatment of HBV infection. More importantly, global collaboration and coordinated approaches are thus needed to facilitate the development of novel therapies for HBV infection.
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Affiliation(s)
- Binbin Hong
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China.,Central Laboratory, the Second Affiliated Hospital of Fujian Medical University, Quanzhou 362000, China
| | - Yumei Wen
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
| | - Tianlei Ying
- Key Laboratory of Medical Molecular Virology of Ministries of Education and Health, School of Basic Medical Sciences, Fudan University, Shanghai 200032, China
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Hossain MG, Mahmud MM, Nazir KHMNH, Ueda K. PreS1 Mutations Alter the Large HBsAg Antigenicity of a Hepatitis B Virus Strain Isolated in Bangladesh. Int J Mol Sci 2020; 21:ijms21020546. [PMID: 31952213 PMCID: PMC7014173 DOI: 10.3390/ijms21020546] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 01/04/2020] [Accepted: 01/13/2020] [Indexed: 02/07/2023] Open
Abstract
Mutations in the hepatitis B virus (HBV) genome can potentially lead to vaccination failure, diagnostic escape, and disease progression. However, there are no reports on viral gene expression and large hepatitis B surface antigen (HBsAg) antigenicity alterations due to mutations in HBV isolated from a Bangladeshi population. Here, we sequenced the full genome of the HBV isolated from a clinically infected patient in Bangladesh. The open reading frames (ORFs) (P, S, C, and X) of the isolated HBV strain were successfully amplified and cloned into a mammalian expression vector. The HBV isolate was identified as genotype C (sub-genotype C2), serotype adr, and evolutionarily related to strains isolated in Indonesia, Malaysia, and China. Clinically significant mutations, such as preS1 C2964A, reverse transcriptase domain I91L, and small HBsAg N3S, were identified. The viral P, S, C, and X genes were expressed in HEK-293T and HepG2 cells by transient transfection with a native subcellular distribution pattern analyzed by immunofluorescence assay. Western blotting of large HBsAg using preS1 antibody showed no staining, and preS1 ELISA showed a significant reduction in reactivity due to amino acid mutations. This mutated preS1 sequence has been identified in several Asian countries. To our knowledge, this is the first report investigating changes in large HBsAg antigenicity due to preS1 mutations.
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Affiliation(s)
- Md. Golzar Hossain
- Division of Virology, Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
- Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.M.M.); (K.H.M.N.H.N.)
- Correspondence: (M.G.H.); (K.U.)
| | - Md. Muket Mahmud
- Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.M.M.); (K.H.M.N.H.N.)
| | - K. H. M. Nazmul Hussain Nazir
- Department of Microbiology and Hygiene, Bangladesh Agricultural University, Mymensingh 2202, Bangladesh; (M.M.M.); (K.H.M.N.H.N.)
| | - Keiji Ueda
- Division of Virology, Department of Microbiology and Immunology, Graduate School of Medicine, Osaka University, Osaka 565-0871, Japan
- Correspondence: (M.G.H.); (K.U.)
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Gao Y, Zhang TY, Yuan Q, Xia NS. Antibody-mediated immunotherapy against chronic hepatitis B virus infection. Hum Vaccin Immunother 2017; 13:1768-1773. [PMID: 28521640 DOI: 10.1080/21645515.2017.1319021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The currently available drugs to treat hepatitis B virus (HBV) infection include interferons and nucleos(t)ide analogs, which can only induce disease remission and are inefficient for the functional cure of patients with chronic HBV infection (CHB). Since high titers of circulating hepatitis B surface antigen (HBsAg) may be essential to exhaust the host anti-HBV immune response and they cannot be significantly reduced by current drugs, new antiviral strategies aiming to suppress serum hepatitis B surface antigen (HBsAg) could help restore virus-specific immune responses and promote the eradication of the virus. As an alternative strategy, immunotherapy with HBsAg-specific antibodies has shown some direct HBsAg suppression effects in several preclinical and clinical trial studies. However, most described previously HBsAg-specific antibodies only had very short-term HBsAg suppression effects in CHB patients and animal models mimicking persistent HBV infection. More-potent antibodies with long-lasting HBsAg clearance effects are required for the development of the clinical application of antibody-mediated immunotherapy for CHB treatment. Our recent study described a novel mAb E6F6 that targets a unique epitope on HBsAg. It could durably suppress the levels of HBsAg and HBV DNA via Fcγ receptor-dependent phagocytosis in vivo. In this commentary, we summarize the current research progress, including the therapeutic roles and mechanisms of antibody-mediated HBV clearance as well as the epitope-determined therapeutic potency of the antibody. These insights may provide some clues and guidance to facilitate the development of therapeutic antibodies against persistent viral infection.
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Affiliation(s)
- Ying Gao
- a State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics , School of Public Health, Xiamen University , Xiamen , China.,b National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science , Xiamen University , Xiamen , China
| | - Tian-Ying Zhang
- a State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics , School of Public Health, Xiamen University , Xiamen , China.,b National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science , Xiamen University , Xiamen , China
| | - Quan Yuan
- a State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics , School of Public Health, Xiamen University , Xiamen , China.,b National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science , Xiamen University , Xiamen , China
| | - Ning-Shao Xia
- a State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics , School of Public Health, Xiamen University , Xiamen , China.,b National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science , Xiamen University , Xiamen , China
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Zhang TY, Yuan Q, Zhao JH, Zhang YL, Yuan LZ, Lan Y, Lo YC, Sun CP, Wu CR, Zhang JF, Zhang Y, Cao JL, Guo XR, Liu X, Mo XB, Luo WX, Cheng T, Chen YX, Tao MH, Shih JW, Zhao QJ, Zhang J, Chen PJ, Yuan YA, Xia NS. Prolonged suppression of HBV in mice by a novel antibody that targets a unique epitope on hepatitis B surface antigen. Gut 2016; 65:658-71. [PMID: 26423112 DOI: 10.1136/gutjnl-2014-308964] [Citation(s) in RCA: 94] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/05/2014] [Accepted: 09/03/2015] [Indexed: 12/12/2022]
Abstract
OBJECTIVE This study aimed to investigate the therapeutic potential of monoclonal antibody (mAb) against HBV as a novel treatment approach to chronic hepatitis B (CHB) in mouse models. METHODS Therapeutic effects of mAbs against various epitopes on viral surface protein were evaluated in mice mimicking persistent HBV infection. The immunological mechanisms of mAb-mediated viral clearance were systematically investigated. RESULTS Among 11 tested mAbs, a novel mAb E6F6 exhibited the most striking therapeutic effects in several HBV-persistent mice. Single-dose administration of E6F6 could profoundly suppress the levels of hepatitis B surface antigen (HBsAg) and HBV DNA for several weeks in HBV-transgenic mice. E6F6 regimen efficiently prevented initial HBV infection, and reduced viral dissemination from infected hepatocytes in human-liver-chimeric mice. E6F6-based immunotherapy facilitated the restoration of anti-HBV T-cell response in hydrodynamic injection (HDI)-based HBV carrier mice. Immunological analyses suggested that the Fcγ receptor-dependent phagocytosis plays a predominant role in E6F6-mediated viral suppression. Molecular analyses suggested that E6F6 recognises an evolutionarily conserved epitope (GPCK(R)TCT) and only forms a smaller antibody-viral particle immune complex with limited interparticle crosslinking when it binds to viral particles. This unique binding characteristic of E6F6 to HBV was possibly associated with its effective in vivo opsonophagocytosis for viral clearance. CONCLUSIONS These results provided new insight into understanding the therapeutic role and mechanism of antibody against persistent viral infection. The E6F6-like mAbs may provide a novel immunotherapeutic agent against human chronic HBV infection.
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Affiliation(s)
- Tian-Ying Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Quan Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Jing-Hua Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Ya-Li Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China Xiamen Blood Services, Xiamen 361002, China
| | - Lun-Zhi Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Ying Lan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Yu-Chieh Lo
- Academia Sinica, Institute of Biomedical Sciences, Taipei, Taiwan
| | - Cheng-Pu Sun
- Academia Sinica, Institute of Biomedical Sciences, Taipei, Taiwan
| | - Chang-Ru Wu
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jun-Fang Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Ying Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Jia-Li Cao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Xue-Ran Guo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Xuan Liu
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Xiao-Bing Mo
- Department of Biological Sciences and Center for Bioimaging Sciences, National University of Singapore, Singapore, 117543, Singapore National University of Singapore (Suzhou) Research Institute, Suzhou 215123, China
| | - Wen-Xin Luo
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Tong Cheng
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Yi-Xin Chen
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Mi-Hua Tao
- Academia Sinica, Institute of Biomedical Sciences, Taipei, Taiwan
| | - James Wk Shih
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Qin-Jian Zhao
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Jun Zhang
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
| | - Pei-Jer Chen
- Department of Internal Medicine, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
| | - Y Adam Yuan
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China Department of Biological Sciences and Center for Bioimaging Sciences, National University of Singapore, Singapore, 117543, Singapore National University of Singapore (Suzhou) Research Institute, Suzhou 215123, China
| | - Ning-Shao Xia
- State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics, School of Life Science & School of Public Health, Xiamen University, Xiamen, China National Institute of Diagnostics and Vaccine Development in Infectious Diseases, School of Life Science & School of Public Health, Xiamen University, Xiamen, China
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Toita R, Kawano T, Kang JH, Murata M. Applications of human hepatitis B virus preS domain in bio- and nanotechnology. World J Gastroenterol 2015; 21:7400-7411. [PMID: 26139986 PMCID: PMC4481435 DOI: 10.3748/wjg.v21.i24.7400] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2015] [Revised: 02/24/2015] [Accepted: 05/04/2015] [Indexed: 02/06/2023] Open
Abstract
Human hepatitis B virus (HBV) is a member of the family Hepadnaviridae, and causes acute and chronic infections of the liver. The hepatitis B surface antigen (HBsAg) contains the large (L), middle (M), and small (S) surface proteins. The L protein consists of the S protein, preS1, and preS2. In HBsAg, the preS domain (preS1 + preS2) plays a key role in the infection of hepatocytic cells by HBV and has several immunogenic epitopes. Based on these characteristics of preS, several preS-based diagnostic and therapeutic materials and systems have been developed. PreS1-specific monoclonal antibodies (e.g., MA18/7 and KR127) can be used to inhibit HBV infection. A myristoylated preS1 peptide (amino acids 2-48) also inhibits the attachment of HBV to HepaRG cells, primary human hepatocytes, and primary tupaia hepatocytes. Antibodies and antigens related to the components of HBsAg, preS (preS1 + preS2), or preS1 can be available as diagnostic markers of acute and chronic HBV infections. Hepatocyte-targeting delivery systems for therapeutic molecules (drugs, genes, or proteins) are very important for increasing the clinical efficacy of these molecules and in reducing their adverse effects on other organs. The selective delivery of diagnostic molecules to target hepatocytic cells can also improve the efficiency of diagnosis. In addition to the full-length HBV vector, preS (preS1 + preS2), preS1, and preS1-derived fragments can be useful in hepatocyte-specific targeting. In this review, we discuss the literature concerning the applications of the HBV preS domain in bio- and nanotechnology.
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Occult HBV infection: a faceless enemy in liver cancer development. Viruses 2014; 6:1590-611. [PMID: 24717680 PMCID: PMC4014712 DOI: 10.3390/v6041590] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2014] [Revised: 03/13/2014] [Accepted: 03/20/2014] [Indexed: 12/12/2022] Open
Abstract
The hepatitis B virus (HBV) represents a worldwide public health problem; the virus is present in one third of the global population. However, this rate may in fact be higher due to occult hepatitis B virus infection (OBI). This condition is characterized by the presence of the viral genome in the liver of individuals sero-negative for the virus surface antigen (HBsAg). The causes of the absence of HBsAg in serum are unknown, however, mutations have been identified that produce variants not recognized by current immunoassays. Epigenetic and immunological host mechanisms also appear to be involved in HBsAg suppression. Current evidence suggests that OBI maintains its carcinogenic potential, favoring the progression of fibrosis and cirrhosis of the liver. In common with open HBV infection, OBI can contribute to the establishment of hepatocellular carcinoma. Epidemiological data regarding the global prevalence of OBI vary due to the use of detection methods of different sensitivity and specificity. In Latin America, which is considered an area of low prevalence for HBV, diagnostic screening methods using gene amplification tests for confirmation of OBI are not conducted. This prevents determination of the actual prevalence of OBI, highlighting the need for the implementation of cutting edge technology in epidemiological surveillance systems.
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Li H, Zhuang Q, Wang Y, Zhang T, Zhao J, Zhang Y, Zhang J, Lin Y, Yuan Q, Xia N, Han J. HBV life cycle is restricted in mouse hepatocytes expressing human NTCP. Cell Mol Immunol 2014; 11:175-83. [PMID: 24509445 DOI: 10.1038/cmi.2013.66] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/09/2013] [Accepted: 12/10/2013] [Indexed: 02/08/2023] Open
Abstract
Recent studies have revealed that human sodium taurocholate cotransporting polypeptide (SLC10A1 or NTCP) is a functional cellular receptor for hepatitis B virus (HBV). However, whether human NTCP can support HBV infection in mouse hepatocyte cell lines has not been clarified. Because an HBV-permissible mouse model would be helpful for the study of HBV pathogenesis, it is necessary to investigate whether human NTCP supports the susceptibility of mouse hepatocyte cell lines to HBV. The results show that exogenous human NTCP expression can render non-susceptible HepG2 (human), Huh7 (human), Hepa1-6 (mouse), AML-12 (mouse) cell lines and primary mouse hepatocyte (PMH) cells susceptible to hepatitis D virus (HDV) which employs HBV envelope proteins. However, human NTCP could only introduce HBV susceptibility in human-derived HepG2 and Huh7 cells, but not in mouse-derived Hepa1-6, AML-12 or PMH cells. These data suggest that although human NTCP is a functional receptor that mediates HBV infection in human cells, it cannot support HBV infection in mouse hepatocytes. Our study indicated that the restriction of HBV in mouse hepatocytes likely occurs after viral entry but prior to viral transcription. We have excluded the role of mouse hepatocyte nuclear factors in the restriction of the HBV life cycle and showed that knockdown or inhibition of Sting, TBK1, IRF3 or IRF7, the components of the anti-viral signaling pathways, had no effect on HBV infection in mouse hepatocytes. Therefore, murine restriction factors that limit HBV infection need to be identified before a HBV-permissible mouse line can be created.
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Affiliation(s)
- Hanjie Li
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, and School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Qiuyu Zhuang
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, and School of Life Sciences, Xiamen University, Xiamen 361005, China
| | - Yuze Wang
- 1] State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, and School of Life Sciences, Xiamen University, Xiamen 361005, China [2] School of Chemical Engineering, Huaqiao University, Xiamen 361005, China
| | - Tianying Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Jinghua Zhao
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Yali Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Junfang Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Yi Lin
- School of Chemical Engineering, Huaqiao University, Xiamen 361005, China
| | - Quan Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Ningshao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Disease, School of Public Health, Xiamen University, Xiamen 361005, China
| | - Jiahuai Han
- State Key Laboratory of Cellular Stress Biology, Innovation Center for Cell Biology, and School of Life Sciences, Xiamen University, Xiamen 361005, China
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Zhu Y, Zhang T, Zhao J, Weng Z, Yuan Q, Li S, Zhang J, Xia N, Zhao Q. Toward the development of monoclonal antibody-based assays to probe virion-like epitopes in hepatitis B vaccine antigen. Hum Vaccin Immunother 2014; 10:1013-23. [PMID: 24499806 DOI: 10.4161/hv.27753] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Prophylactic vaccines against hepatitis B Virus (HBV) infection were produced in different expression systems under different processing conditions. Since the recombinant HBV surface antigen (HBsAg) in these vaccines is a cysteine-rich protein with 14 cysteines among a total of 226 amino acids, the epitopes are dependent on the formation of intra- and intermolecular disulfide bonds. A panel of 22 monoclonal antibodies (mAbs) were developed and evaluated with respect to their sensitivity to disulfide reduction treatment of recombinant HBsAg. Not surprisingly, different mAbs showed different degree of sensitivity to controlled HBsAg disulfide reduction. With a view to exploring the functionality of anti-HBsAg mAbs to be used in HBsAg quality analysis, in vitro neutralization activity for the mAbs was assessed. One of the mAbs tested, 5F11, which showed high sensitivity to the disulfide integrity in HBsAg, was shown also to be highly effective in neutralizing HBV in vitro. Conversely, 42B6, while exhibiting similar neutralization activity, showed comparable binding HBsAg with or without reduction treatment. Based on these mAb characteristics, a sandwich ELISA with 42B6 being the capture Ab and detection Ab was developed to quantify HBsAg (like a "mass" assay) during antigen bioprocessing or in vaccine products. In parallel, when 5F11 was used as the detection Ab (with the same capture Ab), the assay can be used to probe disulfide-dependent and virion-like epitopes in intermediates or final products of hepatitis B vaccine, serving as a surrogate marker for vaccine efficacy to elicit neutralizing antibodies. This approach enables the comparative epitope specific antigenicity analysis of HBsAg antigen preparations from different sources.
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Affiliation(s)
- Yibin Zhu
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China
| | - Tianying Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China
| | - Jinghua Zhao
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China
| | - Zusen Weng
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China
| | - Quan Yuan
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Public Health; Xiamen University; Xiamen, Fujian, PR China
| | - Shaowei Li
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China; School of Public Health; Xiamen University; Xiamen, Fujian, PR China
| | - Jun Zhang
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Public Health; Xiamen University; Xiamen, Fujian, PR China
| | - Ningshao Xia
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Life Sciences; Xiamen University; Xiamen, Fujian, PR China; School of Public Health; Xiamen University; Xiamen, Fujian, PR China
| | - Qinjian Zhao
- National Institute of Diagnostics and Vaccine Development in Infectious Diseases; Xiamen University; Xiamen, Fujian, PR China; State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics; Xiamen University; Xiamen, Fujian, PR China; School of Public Health; Xiamen University; Xiamen, Fujian, PR China
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Alavian SM, Carman WF, Jazayeri SM. HBsAg variants: diagnostic-escape and diagnostic dilemma. J Clin Virol 2012; 57:201-8. [PMID: 22789139 DOI: 10.1016/j.jcv.2012.04.027] [Citation(s) in RCA: 59] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Revised: 01/23/2012] [Accepted: 04/18/2012] [Indexed: 12/11/2022]
Abstract
A wide variety of commercial assays is available for the detection of hepatitis B surface antigen (HBsAg). Clearly, the sensitivity of an assay to detect a variant is dependent on the anti-HBs usage. Thus, it is not surprising that there are examples of variants that cannot be detected by all assays. Data from Europe, Asia and Africa about HBsAg variants which are not recognized by either monoclonal or polyclonal antibodies specific for wild-type group 'a' determinant, but positive by DNA polymerase chain reaction (PCR) in chronic patients and from vaccinated children are increasing. This would impose a challenge for public health issues of hepatitis B virus. In this review we tried to summarize the discrepancies between results of HBsAg assays and to explain some rationales for these inconsistencies.
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Affiliation(s)
- Seyed Moayed Alavian
- Baqiyatallah University of Medical Sciences, Baqiyatallah Research Centre for Gastroenterology and Liver Disease, Tehran, Iran
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Said ZNA. An overview of occult hepatitis B virus infection. World J Gastroenterol 2011; 17:1927-38. [PMID: 21528070 PMCID: PMC3082745 DOI: 10.3748/wjg.v17.i15.1927] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Revised: 01/18/2011] [Accepted: 01/25/2011] [Indexed: 02/06/2023] Open
Abstract
Occult hepatitis B virus (HBV) infection (OBI), alternatively defined as occult hepatitis B (OHB), is a challenging clinical entity. It is recognized by two main characteristics: absence of HBsAg, and low viral replication. The previous two decades have witnessed a remarkable progress in our understanding of OBI and its clinical implications. Appropriate diagnostic techniques must be adopted. Sensitive HBV DNA amplification assay is the gold standard assay for detection of OBI. Viral as well as host factors are implicated in the pathogenesis of OBI. However, published data reporting the infectivity of OBI by transfusion are limited. Several aspects including OBI transmission, infectivity and its relation to the development of chronic liver diseases and hepatocellular carcinoma have to be resolved. The aim of the present review is to highlight recent data on OBI with a focus on its virological diagnosis and clinical outcome.
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