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Zhang JW, Lai RM, Wang LF, Wang SL, Xue HX, Li C, Zheng ZZ, Li J, Zhu YY, Zeng DW, Chen J, Ou QS, Chen TB, Xun Z, Jiang JJ, Zheng Q. Varied immune responses of HBV-specific B cells in patients undergoing pegylated interferon-alpha treatment for chronic hepatitis B. J Hepatol 2024:S0168-8278(24)02338-9. [PMID: 38992769 DOI: 10.1016/j.jhep.2024.06.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 06/21/2024] [Accepted: 06/24/2024] [Indexed: 07/13/2024]
Abstract
BACKGROUND & AIMS The changes of HBV-specific B-cells in chronic hepatitis B (CHB) patients underwent pegylated interferon-alfa (PEG-IFNα) treatment and achieved functional cure remain unclear. We aimed to evaluate the alterations in HBV-specific B-cells during treatment and therefore explored the mechanism of functional recovery of HBsAg-specific B-cells. METHODS We included 39 nucleos(t)ide analogues-treated CHB patients who received sequential combination therapy with PEG-IFNα and 8 treatment-naive CHB patients. HBV-specific B-cells were characterized ex vivo using fluorescent labeled HBsAg and HBcAg. The frequency, phenotype, and subsets of HBV-specific B-cells and follicular helper T cells (Tfh-cells) were detected using flow cytometry. The functionality of HBV-specific B-cells was quantified through ELISpot assays. RESULTS During treatment, the fraction of activated memory B-cells (MBCs) among HBsAg-specific B-cells and the expression of IgG, CXCR3, and CD38 increased. Antibody-secretion capacity of HBsAg-specific B-cell was restored after treatment only in patients with a functional cure and it showed a positive correlation with serum hepatitis B surface antibody levels. The phenotype and function of HBsAg-specific B-cells differed between patients with and without functional cure. Patients with functional cure exhibited IgG+ classical MBCs and plasmablasts in HBsAg-specific B-cells. HBcAg-specific B-cells displayed both attenuated antibody secretion with reduced IgG expression and an IgM+ atypical type of MBCs after treatment, irrespective of with and without functional cure. The number of CD40L+ Tfh-cells increased after PEG-IFNα treatment and positively correlated with HBsAg-specific B-cell activation. CONCLUSIONS After PEG-IFNα treatment, HBsAg- and HBcAg-specific B-cells exhibit various changes in antibody secretion. Their functional differences are reflected in the alterations in phenotypes and subtypes. The presence of CD40L+ Tfh-cells is associated with the active recovery of HBsAg-specific B-cells. IMPACT AND IMPLICATIONS HBV-related complications and hepatocellular carcinoma remain the leading causes of mortality from chronic liver disease worldwide, and a cure is rarely achieved with antiviral therapies. Elucidating the immunological mechanisms underlying the functional cure of CHB patients offers a promising therapeutic strategy for viral clearance, such as therapeutic vaccine. We analyzed the alterations in HBV-specific B-cells in patients treated with PEG-IFNα and identified novel pathways for immunotherapeutic boosting of B cell immunity.
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Affiliation(s)
- Jian-Wei Zhang
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Rui-Min Lai
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Long-Fei Wang
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Si-Ling Wang
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University, Amoy 361100, Fujian Province, China
| | - Han-Xin Xue
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Chen Li
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Zi-Zheng Zheng
- State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, Department of Laboratory Medicine, School of Public Health, Xiamen University, Amoy 361100, Fujian Province, China
| | - Jie Li
- Department of Infectious Disease, Nanjing Drum Tower Hospital, Affiliated Hospital of Medical School, Nanjing University, Nanjing 210000, Jiangsu Province, China
| | - Yue-Yong Zhu
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Da-Wu Zeng
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Jing Chen
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Qi-Shui Ou
- Department of Laboratory Medicine, Fujian Key Laboratory of Laboratory Medicine, Gene Diagnosis Research Center, Fujian Clinical Research Center for Clinical Immunology Laboratory Test, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Tian-Bin Chen
- Department of Laboratory Medicine, Fujian Key Laboratory of Laboratory Medicine, Gene Diagnosis Research Center, Fujian Clinical Research Center for Clinical Immunology Laboratory Test, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China
| | - Zhen Xun
- Department of Laboratory Medicine, Fujian Key Laboratory of Laboratory Medicine, Gene Diagnosis Research Center, Fujian Clinical Research Center for Clinical Immunology Laboratory Test, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China.
| | - Jia-Ji Jiang
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China.
| | - Qi Zheng
- Department of Hepatology, Hepatology Research Institute, The First Affiliated Hospital of Fujian Medical University, Fuzhou 350005, Fujian Province, China; Department of Hepatology, National Regional Medical Center, Binhai Campus of the First Affiliated Hospital, Fujian Medical University, Fuzhou 350005, Fujian Province, China.
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Humoral immunity in hepatitis B virus infection: Rehabilitating the B in HBV. JHEP REPORTS : INNOVATION IN HEPATOLOGY 2022; 4:100398. [PMID: 35059620 PMCID: PMC8760517 DOI: 10.1016/j.jhepr.2021.100398] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 11/08/2021] [Accepted: 11/09/2021] [Indexed: 12/15/2022]
Abstract
Insights into the immunopathogenesis of chronic HBV infections are fundamental in the quest for novel treatment approaches aimed at a functional cure. While much is known about the ineffective HBV-specific T-cell responses that characterise persistent HBV replication, B cells have been left largely understudied. However, an important role for humoral immunity during the natural history of HBV infections, as well as after functional cure, has been inadvertently revealed by the occurrence of HBV flares following B cell-depleting treatments. Herein, we review our current understanding of the role of the humoral immune response in chronic HBV, both at the level of HBV-specific antibody production and at the phenotypic and broader functional level of B cells. The recent development of fluorescently labelled HBV proteins has given us unprecedented insights into the phenotype and function of HBsAg- and HBcAg-specific B cells. This should fuel novel research into the mechanisms behind dysfunctional HBsAg-specific and fluctuating, possibly pathogenic, HBcAg-specific B-cell responses in chronic HBV. Finally, novel immunomodulatory treatments that partly target B cells are currently in clinical development, but a detailed assessment of their impact on HBV-specific B-cell responses is lacking. We plead for a rehabilitation of B-cell studies related to both the natural history of HBV and treatment development programmes.
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Le Bert N, Salimzadeh L, Gill US, Dutertre CA, Facchetti F, Tan A, Hung M, Novikov N, Lampertico P, Fletcher SP, Kennedy PTF, Bertoletti A. Comparative characterization of B cells specific for HBV nucleocapsid and envelope proteins in patients with chronic hepatitis B. J Hepatol 2020; 72:34-44. [PMID: 31348999 DOI: 10.1016/j.jhep.2019.07.015] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/03/2019] [Accepted: 07/09/2019] [Indexed: 12/04/2022]
Abstract
BACKGROUND & AIMS Knowledge about the regulation of anti-HBV humoral immunity during natural HBV infection is limited. We recently utilized dual fluorochrome-conjugated HBsAg to demonstrate, in patients with chronic HBV (CHB) infection, the functional impairment of their HBsAg-specific B cells. However, the features of their HBcAg-specific B cells are unknown. Here we developed a method to directly visualize, select and characterize HBcAg-specific B cells in parallel with HBsAg-specific B cells. METHODS Fluorochrome-conjugated HBcAg reagents were synthesized and utilized to directly detect ex vivo HBcAg-specific B cells in 36 patients with CHB. The frequency, phenotype, functional maturation and transcriptomic profile of HBcAg-specific B cells was studied by flow cytometry, in vitro maturation assays and NanoString-based detection of expression of immune genes, which we compared with HBsAg-specific B cells and total B cells. RESULTS HBcAg-specific B cells are present at a higher frequency than HBsAg-specific B cells in patients with CHB and, unlike HBsAg-specific B cells, they mature efficiently into antibody-secreting cells in vitro. Their phenotypic and transcriptomic profiles show that HBcAg-specific B cells are preferentially IgG+ memory B cells. However, despite their phenotypic and functional differences, HBcAg- and HBsAg-specific B cells from patients with CHB share an mRNA expression pattern that differs from global memory B cells and is characterized by high expression of genes indicative of cross-presentation and innate immune activity. CONCLUSIONS During chronic HBV infection, a direct relation exists between serological detection of anti-HBs and anti-HBc antibodies, and the quantity and function of their respective specific B cells. However, the transcriptomic analysis performed in HBsAg- and HBcAg-specific B cells suggests additional roles of HBV-specific B cells beyond the production of antibodies. LAY SUMMARY Protection of viral infection necessitates the production of antibodies that are generated by specialized cells of the immune system called B cells. During chronic HBV infection, antibodies against the internal part of the virus (core or HBcAg) are detectable while the antibodies directed against the virus envelope (surface or HBsAg) are not present. Here we developed a method that allows us to directly visualize ex vivo the B cells specific for these 2 viral components, highlighting their differences and similarities, and showing how 2 components of the same virus can have different impacts on the function of antiviral B cells.
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Affiliation(s)
- Nina Le Bert
- Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore, Singapore
| | - Loghman Salimzadeh
- Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore, Singapore; Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore
| | - Upkar Singh Gill
- Barts Liver Centre, Barts and The London School of Medicine & Dentistry, Queen Mary University of London, London, UK
| | - Charles-Antoine Dutertre
- Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore, Singapore; Singapore Immunology Network, Singapore Agency for Science, Technology & Research (A*STAR), Singapore, Singapore
| | - Floriana Facchetti
- Gastroenterology and Hepatology Division, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | - Anthony Tan
- Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore, Singapore
| | - Magdeleine Hung
- Gilead Sciences, Department of Biology, Foster City, CA, USA
| | - Nikolai Novikov
- Gilead Sciences, Department of Biology, Foster City, CA, USA
| | - Pietro Lampertico
- Gastroenterology and Hepatology Division, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico, University of Milan, Milan, Italy
| | | | | | - Antonio Bertoletti
- Emerging Infectious Diseases Program, Duke-NUS Medical School, Singapore, Singapore; Singapore Immunology Network, Singapore Agency for Science, Technology & Research (A*STAR), Singapore, Singapore.
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Structure of a patient-derived antibody in complex with allergen reveals simultaneous conventional and superantigen-like recognition. Proc Natl Acad Sci U S A 2018; 115:E8707-E8716. [PMID: 30150373 PMCID: PMC6140506 DOI: 10.1073/pnas.1806840115] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Antibodies classically bind antigens via their complementarity-determining regions, but an alternative mode of interaction involving V-domain framework regions has been observed for some B cell "superantigens." We report the crystal structure of an antibody employing both modes of interaction simultaneously and binding two antigen molecules. This human antibody from an allergic individual binds to the grass pollen allergen Phl p 7. Not only are two allergen molecules bound to each antibody fragment (Fab) but also each allergen molecule is bound by two Fabs: One epitope is recognized classically, the other in a superantigen-like manner. A single allergen molecule thus cross-links two identical Fabs, contrary to the one-antibody-one-epitope dogma, which dictates that a dimeric allergen at least is required for this to occur. Allergens trigger immediate hypersensitivity reactions by cross-linking receptor-bound IgE molecules on effector cells. We found that monomeric Phl p 7 induced degranulation of basophils sensitized solely with this monoclonal antibody expressed as an IgE, demonstrating that the dual specificity has functional consequences. The monomeric state of Phl p 7 and two structurally related allergens was confirmed by size-exclusion chromatography and multiangle laser light scattering, and the results were supported by degranulation studies with the related allergens, a second patient-derived allergen-specific antibody lacking the nonclassical binding site, and mutagenesis of the nonclassically recognized allergen epitope. The antibody dual reactivity and cross-linking mechanism not only have implications for understanding allergenicity and allergen potency but, importantly, also have broader relevance to antigen recognition by membrane Ig and cross-linking of the B cell receptor.
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Veesler D, Kearney BM, Johnson JE. Integration of X-ray crystallography and electron cryo-microscopy in the analysis of virus structure and function. CRYSTALLOGR REV 2015. [DOI: 10.1080/0889311x.2015.1038530] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Sizing up large protein complexes by electrospray ionisation-based electrophoretic mobility and native mass spectrometry: morphology selective binding of Fabs to hepatitis B virus capsids. Anal Bioanal Chem 2013; 406:1437-46. [PMID: 24357008 DOI: 10.1007/s00216-013-7548-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2013] [Revised: 11/29/2013] [Accepted: 12/02/2013] [Indexed: 12/29/2022]
Abstract
The capsid of hepatitis B virus (HBV) is a major viral antigen and important diagnostic indicator. HBV capsids have prominent protrusions ('spikes') on their surface and are unique in having either T = 3 or T = 4 icosahedral symmetry. Mouse monoclonal and also human polyclonal antibodies bind either near the spike apices (historically the 'α-determinant') or in the 'floor' regions between them (the 'β-determinant'). Native mass spectrometry (MS) and gas-phase electrophoretic mobility molecular analysis (GEMMA) were used to monitor the titration of HBV capsids with the antigen-binding domain (Fab) of mAb 3120, which has long defined the β-determinant. Both methods readily distinguished Fab binding to the two capsid morphologies and could provide accurate masses and dimensions for these large immune complexes, which range up to ~8 MDa. As such, native MS and GEMMA provide valuable alternatives to a more time-consuming cryo-electron microscopy analysis for preliminary characterisation of virus-antibody complexes.
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Bereszczak JZ, Rose RJ, van Duijn E, Watts NR, Wingfield PT, Steven AC, Heck AJR. Epitope-distal effects accompany the binding of two distinct antibodies to hepatitis B virus capsids. J Am Chem Soc 2013; 135:6504-12. [PMID: 23597076 PMCID: PMC3658141 DOI: 10.1021/ja402023x] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Infection of humans by hepatitis B virus (HBV) induces the copious production of antibodies directed against the capsid protein (Cp). A large variety of anticapsid antibodies have been identified that differ in their epitopes. These data, and the status of the capsid as a major clinical antigen, motivate studies to achieve a more detailed understanding of their interactions. In this study, we focused on the Fab fragments of two monoclonal antibodies, E1 and 3120. E1 has been shown to bind to the side of outward-protruding spikes whereas 3120 binds to the "floor" region of the capsid, between spikes. We used hydrogen-deuterium exchange coupled to mass spectrometry (HDX-MS) to investigate the effects on HBV capsids of binding these antibodies. Conventionally, capsids loaded with saturating amounts of Fabs would be too massive to be readily amenable to HDX-MS. However, by focusing on the Cp protein, we were able to acquire deuterium uptake profiles covering the entire 149-residue sequence and reveal, in localized detail, changes in H/D exchange rates accompanying antibody binding. We find increased protection of the known E1 and 3120 epitopes on the capsid upon binding and show that regions distant from the epitopes are also affected. In particular, the α2a helix (residues 24-34) and the mobile C-terminus (residues 141-149) become substantially less solvent-exposed. Our data indicate that even at substoichiometric antibody binding an overall increase in the rigidity of the capsid is elicited, as well as a general dampening of its breathing motions.
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Affiliation(s)
- Jessica Z. Bereszczak
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- The Netherlands Proteomics Centre, The Netherlands
| | - Rebecca J. Rose
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- The Netherlands Proteomics Centre, The Netherlands
| | - Esther van Duijn
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- The Netherlands Proteomics Centre, The Netherlands
| | - Norman R. Watts
- Protein Expression Laboratory, National Institute for Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda MD 20892, USA
| | - Paul T. Wingfield
- Protein Expression Laboratory, National Institute for Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda MD 20892, USA
| | - Alasdair C. Steven
- Laboratory of Structural Biology, National Institute for Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda MD 20892, USA
| | - Albert J. R. Heck
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute of Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands
- The Netherlands Proteomics Centre, The Netherlands
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Tang J, Zhang ZH, Liu GL. A systematic analysis of the predicted human La protein targets identified a hepatitis B virus infection signature. J Viral Hepat 2013; 20:12-23. [PMID: 23231080 DOI: 10.1111/j.1365-2893.2012.01626.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The human La (hLa) protein functions in RNA metabolism and is activated by casein kinase 2 (CK2) phosphorylation. Hepatitis B virus (HBV) can exploit hLa to stabilize its RNA and promote its pathogenesis. To enhance our knowledge of host molecular pathways involved in HBV pathogenesis, a bioinformatic approach was used to generate an expression profile of all predicted target genes of CK2-activated hLa in HBV-infected cells. A computerized literature search was performed to identify English language studies of HBV-, hLa- and CK2-related molecules. The data were pooled and the genes were classified in three functional groups by gene ontology (GO) analysis. HBV, hLa and CK2 targets were predicted, respectively, by a computational method, followed by screening for matching gene symbols in the NCBI human sequences, GO, pathway and network analyses. hLa targets and respective networks in the viral mechanisms of HBV were obtained by the final integrative analysis. Thirty-seven hub genes were identified by overlap calculation, suggesting that hLa may play an important role in the development and progression of HBV through cytokine-cytokine receptor interaction, hematopoietic cell lineage, cell adhesion molecules (CAMs), antigen processing and presentation, Jak-STAT signalling pathway, natural killer cell-mediated cytotoxicity, apoptosis, T-cell receptor signalling pathway, complement and coagulation cascades, protein export and other pathways. Our data may help researchers to predict the molecular mechanisms of hLa in the development and progression of HBV through CK2 comprehensively. Moreover, the present data indicate that hLa targets may be a series of promising candidates for HBV.
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Affiliation(s)
- J Tang
- Department of Pharmacy, First People's Hospital Affiliated to Shanghai JiaoTong University, Shanghai, China
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Wu W, Chen Z, Cheng N, Watts NR, Stahl SJ, Farci P, Purcell RH, Wingfield PT, Steven AC. Specificity of an anti-capsid antibody associated with Hepatitis B Virus-related acute liver failure. J Struct Biol 2012; 181:53-60. [PMID: 23079477 DOI: 10.1016/j.jsb.2012.10.004] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2012] [Revised: 10/01/2012] [Accepted: 10/08/2012] [Indexed: 12/11/2022]
Abstract
Previously, the livers of patients suffering from acute liver failure (ALF), a potentially fatal syndrome arising from infection by Hepatitis B Virus (HBV), were found to contain massive amounts of an antibody specific for the core antigen (HBcAg) capsid. We have used cryo-electron microscopy and molecular modeling to define its epitope. HBV capsids are icosahedral shells with 25Å-long dimeric spikes, each a 4-helix bundle, protruding from the contiguous "floor". Of the anti-HBcAg antibodies previously characterized, most bind around the spike tip while one binds to the floor. The ALF-associated antibody binds tangentially to a novel site on the side of the spike. This epitope is conformational. The Fab binds with high affinity to its principal determinants but has lower affinities for quasi-equivalent variants. The highest occupancy site is on one side of a spike, with no detectable binding to the corresponding site on the other side. Binding of one Fab per dimer was also observed by analytical ultracentrifugation. The Fab did not bind to the e-antigen dimer, a non-assembling variant of capsid protein. These findings support the propositions that antibodies with particular specificities may correlate with different clinical expressions of HBV infection and that antibodies directed to particular HBcAg epitopes may be involved in ALF pathogenesis.
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Affiliation(s)
- Weimin Wu
- Laboratory of Structural Biology, National Institute for Arthritis, Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, United States
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Wang XD, Wang L, Ji FJ, Zhu JM, Ayana DA, Fang XD. Decreased CD27 on B lymphocytes in patients with primary hepatocellular carcinoma. J Int Med Res 2012; 40:307-16. [PMID: 22429370 DOI: 10.1177/147323001204000131] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
OBJECTIVES Hepatitis B virus (HBV) replicates in the liver and can lead to hepatocellular carcinoma (HCC). The B lymphocytes may provide a means for HBV to persist although the mechanism remains unknown. This study aimed to characterize B lymphocyte subset phenotypes and measure levels of B lymphocyte-related cytokines in HCC patients. METHODS The study population included 38 HCC patients and 30 healthy control subjects. Phenotyping of B lymphocytes was performed by flow cytometry. Serum cytokine levels were measured using a cytometric bead array immunoassay. RESULTS The ratio of naïve (CD29+CD27-) to memory (CD19+CD27+) B lymphocytes was significantly higher in HCC patients compared with healthy controls. The percentage of memory B lymphocytes decreased with the progression of HCC. Levels of interleukin (IL)-6 and IL-10 were significantly increased in HCC patients compared with healthy controls. CONCLUSIONS The depletion of memory B lymphocytes may contribute to unresponsiveness to HBV or to HCC. This humoral defect might be related to raised production of IL-6 and IL-10.
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Affiliation(s)
- X D Wang
- Department of General Surgery, General Surgery Centre of Jilin University, The Second Hospital, Jilin University, Changchun, China
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11
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Ranka R, Petrovskis I, Sominskaya I, Bogans J, Bruvere R, Akopjana I, Ose V, Timofejeva I, Brangulis K, Pumpens P, Baumanis V. Fibronectin-binding nanoparticles for intracellular targeting addressed by B. burgdorferi BBK32 protein fragments. NANOMEDICINE-NANOTECHNOLOGY BIOLOGY AND MEDICINE 2012; 9:65-73. [PMID: 22633898 DOI: 10.1016/j.nano.2012.05.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/22/2011] [Revised: 04/17/2012] [Accepted: 05/02/2012] [Indexed: 11/30/2022]
Abstract
UNLABELLED Virus-like particles (VLPs) are created by the self-assembly of multiple copies of envelope and/or capsid proteins from many viruses, mimicking the conformation of a native virus. Such noninfectious nanostructures are mainly used as antigen-presenting platforms, especially in vaccine research; however, some of them recently were used as scaffolds in biotechnology to produce targeted nanoparticles for intracellular delivery. This study demonstrates the creation of fusion VLPs using hepatitis B core protein-based system maintaining a fibronectin-binding property from B. burgdorferi BBK32 protein, including the evidence of particles' transmission to BHK-21 target cells via caveolae/rafts endocythosis. These results make this construct to be an attractive model in development of HBc-based nanoparticles for cellular targeting applications and highlights the fragment of B. burgdorferi BBK32 as a novel cellular uptake-promoting peptide. FROM THE CLINICAL EDITOR This paper discusses the nanotechnology-based application of self-assembling viral-like peptides (VLP-s) for targeted delivery using a hepatitis B core protein based system. Creating fusion VLPs may be an attractive model for cellular targeting applications.
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Affiliation(s)
- Renate Ranka
- Latvian Biomedical Research and Study Centre, Riga, Latvia.
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Kandiah E, Watts NR, Cheng N, Cardone G, Stahl SJ, Heller T, Liang TJ, Wingfield PT, Steven AC. Cryo-EM study of Hepatitis B virus core antigen capsids decorated with antibodies from a human patient. J Struct Biol 2011; 177:145-51. [PMID: 22056468 DOI: 10.1016/j.jsb.2011.10.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2011] [Revised: 10/15/2011] [Accepted: 10/18/2011] [Indexed: 01/23/2023]
Abstract
The capsid (core antigen, HBcAg) is one of three major antigens present in patients infected with Hepatitis B virus. The capsids are icosahedral particles, whose most prominent features are spikes that extend 25 Å out from the contiguous "floor". At the spike tip are two copies of the "immunodominant loop". Previously, the epitopes of seven murine monoclonal antibodies have been identified by cryo-EM analysis of Fab-labeled capsids. All but one are conformational and all but one map around the spike tip. The exception, which is also the tightest-binder, straddles an inter-molecular interface on the floor. Seeking to relate these observations to the immunological response of infected humans, we isolated anti-cAg antibodies from a patient, prepared Fabs, and analyzed their binding to capsids. A priori, one possibility was that many different Fabs would give an undifferentiated continuum of Fab-related density. In fact, the density observed was highly differentiated and could be reproduced by modeling with just five Fabs, three binding to the spike and two to the floor. These results show that epitopes on the floor, far (~30 Å) from the immunodominant loop, are clinically relevant and that murine anti-cAg antibodies afford a good model for the human system.
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Affiliation(s)
- Eaazhisai Kandiah
- Laboratory of Structural Biology Research, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA
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Watts NR, Vethanayagam JG, Ferns RB, Tedder RS, Harris A, Stahl SJ, Steven AC, Wingfield PT. Molecular basis for the high degree of antigenic cross-reactivity between hepatitis B virus capsids (HBcAg) and dimeric capsid-related protein (HBeAg): insights into the enigmatic nature of the e-antigen. J Mol Biol 2010; 398:530-41. [PMID: 20307545 DOI: 10.1016/j.jmb.2010.03.026] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2010] [Revised: 03/11/2010] [Accepted: 03/13/2010] [Indexed: 12/21/2022]
Abstract
The hepatitis B virus core gene codes for two closely related antigens: a 21-kDa protein that forms dimers that assemble as multimegadalton capsids, and a 17-kDa protein that also forms dimers but that do not assemble. The proteins, respectively referred to as core antigen (HBcAg) and e-antigen (HBeAg), share a sequence of 149 residues but have different amino- and carboxy-termini. Their structural and serological relationship has long been unclear. With insights gained from recent structural studies on immune complexes of the capsids, the relationship was reassessed using recombinant forms of the antigens and a panel of monoclonal antibodies (mAbs) commonly believed to discriminate between core and e-antigen. Surface plasmon resonance (SPR) was used to measure the affinities, in contrast to previous studies that used more error-prone and less sensitive plate-type assays. Four of the six mAbs did not discriminate between core and e-antigen, nor did they discriminate between e-antigen and dimers of dissociated core antigen capsids. One mAb (3120) was specific for assembled capsids and one (e6) was specific for unassembled dimers. Epitope valency of the e-antigen was also studied, using a sandwich SPR assay where e-antigen was captured with one mAb and probed with a second. The e-antigen is often considered to be a monomeric protein on the basis of monovalent reactivity with antibody pairs specific for either an alpha or beta epitope (in a prior nomenclature for e-antigen specificity). This model, however, is incorrect, because recombinant e-antigen is a stable dimer and its apparent monovalency is due to steric blockage. This was proven by the formation of a 2:1 Fab e6-e-antigen complex. These results suggest new approaches for the isolation of the authentic e-antigen, its biological assay, and its stabilization as an immune complex for structural studies.
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Affiliation(s)
- Norman R Watts
- Protein Expression Laboratory, National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, MD 20892, USA.
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Rich RL, Myszka DG. Grading the commercial optical biosensor literature-Class of 2008: 'The Mighty Binders'. J Mol Recognit 2010; 23:1-64. [PMID: 20017116 DOI: 10.1002/jmr.1004] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Optical biosensor technology continues to be the method of choice for label-free, real-time interaction analysis. But when it comes to improving the quality of the biosensor literature, education should be fundamental. Of the 1413 articles published in 2008, less than 30% would pass the requirements for high-school chemistry. To teach by example, we spotlight 10 papers that illustrate how to implement the technology properly. Then we grade every paper published in 2008 on a scale from A to F and outline what features make a biosensor article fabulous, middling or abysmal. To help improve the quality of published data, we focus on a few experimental, analysis and presentation mistakes that are alarmingly common. With the literature as a guide, we want to ensure that no user is left behind.
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Affiliation(s)
- Rebecca L Rich
- Center for Biomolecular Interaction Analysis, University of Utah, Salt Lake City, UT 84132, USA
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Lee BO, Tucker A, Frelin L, Sallberg M, Jones J, Peters C, Hughes J, Whitacre D, Darsow B, Peterson DL, Milich DR. Interaction of the hepatitis B core antigen and the innate immune system. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2009; 182:6670-81. [PMID: 19454661 PMCID: PMC2685464 DOI: 10.4049/jimmunol.0803683] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Previous studies demonstrated that the primary APCs for the hepatitis B core Ag (HBcAg) were B cells and not dendritic cells (DC). We now report that splenic B1a and B1b cells more efficiently present soluble HBcAg to naive CD4(+) T cells than splenic B2 cells. This was demonstrated by direct HBcAg-biotin-binding studies and by HBcAg-specific T cell activation in vitro in cultures of naive HBcAg-specific T cells and resting B cell subpopulations. The inability of DC to function as APCs for exogenous HBcAg relates to lack of uptake of HBcAg, not to processing or presentation, because HBcAg/anti-HBc immune complexes can be efficiently presented by DC. Furthermore, HBcAg-specific CD4(+) and CD8(+) T cell priming with DNA encoding HBcAg does not require B cell APCs. TLR activation, another innate immune response, was also examined. Full-length (HBcAg(183)), truncated (HBcAg(149)), and the nonparticulate HBeAg were screened for TLR stimulation via NF-kappaB activation in HEK293 cells expressing human TLRs. None of the HBc/HBeAgs activated human TLRs. Therefore, the HBc/HBeAg proteins are not ligands for human TLRs. However, the ssRNA contained within HBcAg(183) does function as a TLR-7 ligand, as demonstrated at the T and B cell levels in TLR-7 knockout mice. Bacterial, yeast, and mammalian ssRNA encapsidated within HBcAg(183) all function as TLR-7 ligands. These studies indicate that innate immune mechanisms bridge to and enhance the adaptive immune response to HBcAg and have important implications for the use of hepadnavirus core proteins as vaccine carrier platforms.
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Affiliation(s)
- Byung O Lee
- Vaccine Research Institute of San Diego, San Diego, CA 92109, USA
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