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1.
J Phys Chem Lett ; 12(5): 1438-1442, 2021 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-33523655

RESUMO

The dramatic impact novel viruses can have on humans could be more quickly mitigated if generic antibodies already present in one's system are temporarily retrained to recognize these viruses. This type of intervention can be administered during the early stages of infection, while a specific immune response is being developed. With this idea in mind, double-faced peptide-based boosters were computationally designed to allow recognition of SARS-CoV-2 by Hepatitis B antibodies. One booster face is made of ACE2-mimic peptides that can bind to the receptor binding domain (RBD) of SARS-CoV-2. The other booster face is composed of a Hepatitis B core-antigen, targeting the Hepatitis B antibody fragment. Molecular dynamics simulations revealed that the designed boosters have a highly specific and stable binding to both the RBD and the antibody fragment (AF). This approach can provide a cheap and efficient neutralization of emerging pathogens.


Assuntos
Anticorpos Anti-Hepatite B/química , SARS-CoV-2/química , Sequência de Aminoácidos , Enzima de Conversão de Angiotensina 2/química , Sítios de Ligação , Humanos , Fragmentos de Imunoglobulinas/química , Simulação de Dinâmica Molecular , Peptídeos/química , Ligação Proteica , Conformação Proteica , Anticorpos de Cadeia Única/química , Termodinâmica
2.
J Immunol Methods ; 458: 26-32, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29654816

RESUMO

Hepatitis B virus (HBV) infection is the major public health problem leading cause of death worldwide. The most important diagnostic marker for this infection is hepatitis B surface antigen (HBsAg). In this study, a novel, inexpensive, portable and sensitive ELISA method was designed and investigated for diagnosis of HBsAg based on the functionalized Fe3O4 and Al2O3 nanoparticles, with the strategy for detecting the concentration of glucose using a cheap and accessible personal glucose meter (PGM). The ELISA system was constructed using hepatitis B antibody against HBsAg immobilized on streptavidin coated magnetic iron oxide particles (S-Fe3O4) as the capture antibody (Ab1). In addition, another hepatitis B antibody against different epitope of HBsAg (Ab2) and glucoamylase both were immobilized on Al2O3 nanoparticles. After formation of the sandwich immune complex between Ab1 and Ab2 immobilized on S-Fe3O4 and Al2O3 NPs, respectively, through HBsAg, starch was converted into glucose using glucoamylase. Then, the glucose concentration was measured using PGM. The concentration of HBsAg was calculated based on the linear relation between the concentrations of HBsAg and glucose. Under optimal conditions, this assay showed detection limit values of 0.3 to 0.4 ng ml-1 for "ay" and "ad" subtypes of HBsAg, respectively. The results indicate that the designed assay is comparable to the commercial kits in terms of sensitivity, on-site, specificity, cost, simplicity, portability and reproducibility. The presented method can be used in disadvantaged areas of the world and blood transfusion centers. To the best of our knowledge, this is the first report of using PGMs for HBSAg detection.


Assuntos
Técnicas Biossensoriais/instrumentação , Glicemia/análise , Antígenos de Superfície da Hepatite B/isolamento & purificação , Vírus da Hepatite B/isolamento & purificação , Hepatite B/diagnóstico , Anticorpos Imobilizados/química , Anticorpos Imobilizados/imunologia , Técnicas Biossensoriais/economia , Técnicas Biossensoriais/métodos , Glicemia/metabolismo , Ensaio de Imunoadsorção Enzimática/economia , Ensaio de Imunoadsorção Enzimática/instrumentação , Ensaio de Imunoadsorção Enzimática/métodos , Epitopos/imunologia , Glucana 1,4-alfa-Glucosidase/química , Glucana 1,4-alfa-Glucosidase/imunologia , Glucana 1,4-alfa-Glucosidase/metabolismo , Hepatite B/sangue , Hepatite B/virologia , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/sangue , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Limite de Detecção , Nanopartículas de Magnetita/química , Kit de Reagentes para Diagnóstico/economia , Reprodutibilidade dos Testes
3.
Electrophoresis ; 39(2): 406-416, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28972666

RESUMO

Circulating immune complexes (CICs) are produced during the immune response. It is more clinically important to establish a general and efficient CICs dissociation technique for the detection of antigens for CICs other than the detection of free antigens in the serum. Polyethylene glycol (PEG) two-precipitation separation and glycine-HCl as a buffer system were employed to develop a general and efficient buffer dissociation technique to separate CICs from serum and dissociate antigens from CICs. The measurement value of new PEG two-precipitation separation technique was higher than traditional PEG precipitation separation technique. There were slight differences in the dissociation conditions of HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC as compared to HBsAg-IC. The detection of antigens in HBsAg-IC, HCV Core-IC, HIV P24-IC, Ins-IC and TG-IC with this technique was superior to that with HCl Dissociation, Trypsin Digestion or Immune Complex Transfer technique. PEG two-precipitation dissociation technique may reduce macromolecular protein and the adhesion of free antigens during the co-precipitation, which increases the efficiency of separation and precipitation of CICs. This technique also avoids the damage of reagents to antigens, assuring the repeatability, reliability and validity. Thus, this technique is application in samples negative or positive for free antigens.


Assuntos
Complexo Antígeno-Anticorpo/sangue , Complexo Antígeno-Anticorpo/química , Precipitação Química , Complexo Antígeno-Anticorpo/isolamento & purificação , Estudos de Casos e Controles , Ensaio de Imunoadsorção Enzimática , Glicina/química , Hepatite B/sangue , Hepatite B/imunologia , Anticorpos Anti-Hepatite B/sangue , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/isolamento & purificação , Antígenos de Superfície da Hepatite B/sangue , Antígenos de Superfície da Hepatite B/química , Antígenos de Superfície da Hepatite B/isolamento & purificação , Humanos , Polietilenoglicóis/química
4.
J Biol Chem ; 292(40): 16760-16772, 2017 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-28842495

RESUMO

Hepatitis B virus (HBV) infection afflicts millions worldwide, causing cirrhosis and liver cancer. HBV e-antigen (HBeAg), a clinical marker for disease severity, is a soluble variant of the viral capsid protein. HBeAg is not required for viral replication but is implicated in establishing immune tolerance and chronic infection. The structure of recombinant e-antigen (rHBeAg) was recently determined, yet to date, the exact nature and quantitation of HBeAg still remain uncertain. Here, to further characterize HBeAg, we used phage display to produce a panel of chimeric rabbit/human monoclonal antibody fragments (both Fab and scFv) against rHBeAg. Several of the Fab/scFv, expressed in Escherichia coli, had unprecedentedly high binding affinities (Kd ∼10-12 m) and high specificity. We used Fab/scFv in the context of an enzyme-linked immunosorbent assay (ELISA) for HBeAg quantification, which we compared with commercially available kits and verified with seroconversion panels, the WHO HBeAg standard, rHBeAg, and patient plasma samples. We found that the specificity and sensitivity are superior to those of existing commercial assays. To identify potential fine differences between rHBeAg and HBeAg, we used these Fabs in microscale immunoaffinity chromatography to purify HBeAg from individual patient plasmas. Western blotting and MS results indicated that rHBeAg and HBeAg are essentially structurally identical, although HBeAg from different patients exhibits minor carboxyl-terminal heterogeneity. We discuss several potential applications for the humanized Fab/scFv.


Assuntos
Anticorpos Anti-Hepatite B/imunologia , Antígenos E da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Hepatite B/imunologia , Proteínas Recombinantes de Fusão/imunologia , Anticorpos de Cadeia Única/imunologia , Animais , Ensaio de Imunoadsorção Enzimática/métodos , Hepatite B/sangue , Hepatite B/tratamento farmacológico , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/genética , Anticorpos Anti-Hepatite B/uso terapêutico , Antígenos E da Hepatite B/sangue , Antígenos E da Hepatite B/química , Vírus da Hepatite B/química , Humanos , Coelhos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/uso terapêutico , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/genética , Anticorpos de Cadeia Única/uso terapêutico
5.
World J Gastroenterol ; 22(35): 8010-6, 2016 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-27672295

RESUMO

The scarcity of available organs and the gap between supply and demand continue to be the main limitations of liver transplantation. To relieve the organ shortage, current transplant strategies have implemented extended criteria, which include the use of liver from patients with signs of past or present hepatitis B virus (HBV) infection. While the use of liver grafts from donors with evidence of past HBV infection is quite limited, some data have been collected regarding the feasibility of transplanting a liver graft from a hepatitis B surface antigen (HBsAg) positive donor. The aim of the present work was to review the literature regarding liver transplants from HBsAg-positive donors. A total of 17 studies were identified by a search in Medline. To date, HBsAg positive grafts have preferentially been allocated to HBsAg positive recipients. The large majority of these patients continue to be HBsAg positive despite the use of immunoglobulin, and infection prevention can only be guaranteed by using antiviral prophylaxis. Although serological persistence is evident, no significant HBV-related disease has been observed, except in patients coinfected with delta virus. Consistently less data are available for HBsAg negative recipients, although they are mostly promising. HBsAg-positive grafts could be an additional organ source for liver transplantation, provided that the risk of reinfection/reactivation is properly prevented.


Assuntos
Antígenos de Superfície da Hepatite B/química , Hepatite B/prevenção & controle , Falência Hepática/cirurgia , Transplante de Fígado/métodos , Doadores de Tecidos , Antivirais/uso terapêutico , Sobrevivência de Enxerto , Anticorpos Anti-Hepatite B/química , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Imunoglobulinas/uso terapêutico , Lamivudina/uso terapêutico , Fígado/imunologia , Falência Hepática/terapia , Risco
6.
Artigo em Russo | MEDLINE | ID: mdl-30695452

RESUMO

AIM: Study antigen-binding ability of polyclonal antibodies (PCA) of chicken compared with monoclonal -antibodies (MCA) of mice in the model of interaction with HBsAg. MATERIALS AND METHODS: Mice MCA 18C8 and MKA F3/F4 (IgG) were used, effective in enzyme immunoassay sandwich method of HBsAg determination (with a minimal detection dose of 0.017 ng/ml), and affinity purified anti-HBsAg PCA of chicken (IgY), obtained from 2 immunized birds (PCA No. 1 and PCA No. 2). The ability of antibodies to bind HBsAg was evaluated by analytical sensitivity (slope of binding curve) of solid-phase enzyme immunoassay system using mice MCA and chicken PCA. RESULTS: PCA No. 2 has provided a statistically significant 40% increase of analytical sensitivity, compared with <

Assuntos
Anticorpos Anti-Hepatite B/química , Antígenos de Superfície da Hepatite B/sangue , Hepatite B/sangue , Imunoglobulinas/química , Animais , Galinhas , Ensaio de Imunoadsorção Enzimática/métodos , Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Humanos , Camundongos
7.
BMC Biotechnol ; 15: 85, 2015 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-26370129

RESUMO

BACKGROUND: Virus-like particles (VLPs) can be efficiently produced by heterologous expression of viral structural proteins in yeast. Due to their repetitive structure, VLPs are extensively used for protein engineering and generation of chimeric VLPs with inserted foreign epitopes. Hamster polyomavirus VP1 represents a promising epitope carrier. However, insertion of large sized protein sequences may interfere with its self-assembly competence. The co-expression of polyomavirus capsid protein VP1 with minor capsid protein VP2 or its fusion protein may result in pseudotype VLPs where an intact VP1 protein mediates VLP formation. In the current study, the capacity of VP1 protein to self-assemble to VLPs and interact with the modified VP2 protein has been exploited to generate pseudotype VLPs displaying large-sized antibody molecules. RESULTS: Polyomavirus-derived pseudotype VLPs harbouring a surface-exposed functionally active neutralizing antibody specific to hepatitis B virus (HBV) surface antigen (HBsAg) have been generated. The pseudotype VLPs consisting of an intact hamster polyomavirus (HaPyV) major capsid protein VP1 and minor capsid protein VP2 fused with the anti-HBsAg molecule were efficiently produced in yeast Saccharomyces cerevisiae and purified by density-gradient centrifugation. Formation of VLPs was confirmed by electron microscopy. Two types of pseudotype VLPs were generated harbouring either the single-chain fragment variable (scFv) or Fc-engineered scFv on the VLP surface. The antigen-binding activity of the purified pseudotype VLPs was evaluated by ELISA and virus-neutralization assay on HBV-susceptible primary hepatocytes from Tupaia belangeri. Both types of the pseudotype VLPs were functionally active and showed a potent HBV-neutralizing activity comparable to that of the parental monoclonal antibody. The VP2-fused scFv molecules were incorporated into the VLPs with higher efficiency as compared to the VP2-fused Fc-scFv. However, the pseudotype VLPs with displayed VP2-fused Fc-scFv molecule showed higher antigen-binding activity and HBV-neutralizing capacity that might be explained by a better accessibility of the Fc-engineered scFv of the VLP surface. CONCLUSIONS: Polyomavirus-derived pseudotype VLPs harbouring multiple functionally active antibody molecules with virus-neutralizing capability may represent a novel platform for developing therapeutic tools with a potential application for post-exposure or therapeutic treatment of viral infections.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Vacinas contra Hepatite B , Polyomavirus/genética , Vacinas de Partículas Semelhantes a Vírus , Animais , Anticorpos Neutralizantes/química , Anticorpos Neutralizantes/genética , Células Cultivadas , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/genética , Vacinas contra Hepatite B/química , Vacinas contra Hepatite B/genética , Vacinas contra Hepatite B/imunologia , Hepatócitos/citologia , Hepatócitos/virologia , Polyomavirus/química , Saccharomyces cerevisiae , Tupaia , Vacinas de Partículas Semelhantes a Vírus/química , Vacinas de Partículas Semelhantes a Vírus/genética , Vacinas de Partículas Semelhantes a Vírus/imunologia
8.
FEBS Lett ; 589(2): 193-200, 2015 Jan 16.
Artigo em Inglês | MEDLINE | ID: mdl-25481411

RESUMO

To improve a previously constructed broadly neutralizing hepatitis B virus (HBV)-specific preS1 humanized antibody (HzKR127), we further humanized it through specificity-determining residue (SDR) grafting. Moreover, we improved affinity by mutating two residues in heavy-chain complementarity-determining regions (CDR), on the basis of the crystal structure of the antigen-antibody complex. HzKR127-3.2 exhibited 2.5-fold higher affinity and enhanced virus-neutralizing activity compared to the original KR127 antibody and showed less immunogenic potential than HzKR127. Enhanced virus-neutralizing activity was achieved by the increased association rate, providing insights into engineering potent antibody therapeutics for HBV immunoprophylaxis. HzKR127-3.2 may be a good candidate for HBV immunoprophylaxis.


Assuntos
Complexo Antígeno-Anticorpo , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Sequência de Aminoácidos , Animais , Linhagem Celular , Epitopos de Linfócito T/imunologia , Anticorpos Anti-Hepatite B/farmacologia , Humanos , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Estrutura Terciária de Proteína , Proteínas Virais/química , Proteínas Virais/imunologia
9.
Curr Issues Mol Biol ; 16: 69-78, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24014801

RESUMO

Hepatitis B virus infection is a serious health problem worldwide, and more than 350 million people are chronic carriers, constituting a major global threat. Southeast Asia and the Western Pacific have the highest levels of endemicity in the world, with an estimated seroprevalence ranging between 2% and 31%. Mutations in the hepatitis B surface antigen (HBsAg) have been reported in many parts of the world but are most common in Asian infants; such mutants have several clinical effects, such as the development of hepatocellular carcinoma. Diagnostic failures by commercial assays have reduced the diagnostic effectiveness of HBsAg detection. For example the substitution of an amino acid in the major hydrophilic region of the S gene reduces the binding of hepatitis B surface antibodies leading to immune escape. The safety of blood transfusion may be compromised by current screening tests due to escape from being neutralised by antibodies induced by HBsAg mutants, and undetectable levels of viral surface protein. Data on the epidemiology of HBsAg mutation in Asia Pacific are scant; however, this manuscript has reviewed the available information on the epidemiology of HBsAg mutation in Asia Pacific.


Assuntos
Anticorpos Anti-Hepatite B/química , Antígenos de Superfície da Hepatite B/genética , Vírus da Hepatite B/genética , Hepatite B/diagnóstico , Mutação , Substituição de Aminoácidos , Ásia/epidemiologia , Carcinoma Hepatocelular/epidemiologia , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/virologia , Hepatite B/complicações , Hepatite B/epidemiologia , Hepatite B/virologia , Antígenos de Superfície da Hepatite B/isolamento & purificação , Vírus da Hepatite B/patogenicidade , Humanos , Lactente , Neoplasias Hepáticas/epidemiologia , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/virologia , Tipagem Molecular/métodos , Estudos Soroepidemiológicos
10.
J Struct Biol ; 181(1): 53-60, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23079477

RESUMO

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.


Assuntos
Anticorpos Anti-Hepatite B/química , Vírus da Hepatite B/imunologia , Proteínas do Core Viral/química , Proteínas do Core Viral/imunologia , Especificidade de Anticorpos , Cromatografia de Afinidade , Microscopia Crioeletrônica , Mapeamento de Epitopos , Hepatite B/imunologia , Hepatite B/virologia , Vírus da Hepatite B/ultraestrutura , Humanos , Falência Hepática Aguda/imunologia , Falência Hepática Aguda/virologia , Modelos Moleculares , Estrutura Quaternária de Proteína , Estrutura Secundária de Proteína , Proteínas do Core Viral/isolamento & purificação
11.
J Mol Biol ; 423(1): 63-78, 2012 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-22750730

RESUMO

The core shell of hepatitis B virus is a potent immune stimulator, giving a strong neutralizing immune response to foreign epitopes inserted at the immunodominant region, located at the tips of spikes on the exterior of the shell. Here, we analyze structures of core shells with a model epitope inserted at two alternative positions in the immunodominant region. Recombinantly expressed core protein assembles into T=3 and T=4 icosahedral shells, and atomic coordinates are available for the T=4 shell. Since the modified protein assembles predominantly into T=3 shells, a quasi-atomic model of the native T=3 shell was made. The spikes in this T=3 structure resemble those in T=4 shells crystallized from expressed protein. However, the spikes in the modified shells exhibit an altered conformation, similar to the DNA containing shells in virions. Both constructs allow full access of antibodies to the foreign epitope, DPAFR from the preS1 region of hepatitis B virus surface antigen. However, one induces a 10-fold weaker immune response when injected into mice. In this construct, the epitope is less constrained by the flanking linker regions and is positioned so that the symmetry of the shell causes pairs of epitopes to come close enough to interfere with one another. In the other construct, the epitope mimics the native epitope conformation and position. The interaction of native core shells with an antibody specific to the immunodominant epitope is compared to the constructs with an antibody against the foreign epitope. Our findings have implications for the design of vaccines based on virus-like particles.


Assuntos
Complexo Antígeno-Anticorpo/imunologia , Epitopos/imunologia , Anticorpos Anti-Hepatite B/imunologia , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Sequência de Aminoácidos , Animais , Complexo Antígeno-Anticorpo/química , Epitopos/química , Anticorpos Anti-Hepatite B/química , Antígenos do Núcleo do Vírus da Hepatite B/química , Antígenos de Superfície da Hepatite B/química , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/química , Camundongos , Dados de Sequência Molecular , Conformação Proteica
12.
IET Nanobiotechnol ; 6(1): 9-15, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-22423865

RESUMO

The protein-protein interactions between hepatitis B surface antigen (HBsAg) and its antibodies (anti-HBs) were studied by measuring the binding force between microspheres coated with such proteins using optical tweezers. The interaction force between the protein-coated microspheres was found to be strongly influenced by the acidity of the surrounding liquid medium, as well as the experimental temperature, and it reaches a maximum value at around pH 7.5 and temperature around 37°C. By measuring the protein distribution on the surfaces of the microspheres and their contact areas using scanning electron microscopy, the specific binding force between an HBsAg and anti-HBs protein pair is estimated to be around 4.8 pN at the optimum pH value and temperature at an applied loading rate of around 1 pN/s.


Assuntos
Complexo Antígeno-Anticorpo/química , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/química , Antígenos de Superfície da Hepatite B/imunologia , Pinças Ópticas , Ligação Proteica
13.
J Clin Virol ; 52(4): 295-9, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21978612

RESUMO

BACKGROUND: Currently, quantitative measurement of serum markers of HBV infection has been widely used, but commonly used analysis for specific antibodies only involves the measurement of the total antibody activity, and the binding affinity or protein content is rarely analyzed. OBJECTIVE: To investigate the detailed features of an antibody to hepatitis B core antigen (anti-HBc) during different periods of hepatitis B virus (HBV) infection with a new method of analysis. STUDY DESIGN: Serum samples were collected from patients that were positive for the anti-HBc antibody. On the basis of the other serological markers in the samples, all patients were divided into a hepatitis B surface antigen (HBsAg)-positive group and an antibody to hepatitis B surface antigen (anti-HBs)-positive group. All samples were diluted 2-, 20- and 200-fold. Anti-HBc quantification was measured with a chemiluminescent microparticle immunoassay; total anti-HBc activity, protein content and affinity were calculated according to a measured value of each dilution. Serum HBV DNA load and alanine aminotransferase (ALT) levels were also measured. RESULTS: The total anti-HBc activity in the HBsAg-positive group was statistically higher than that in the anti-HBs-positive group (p<0.05). The anti-HBc protein content during active HBV infection was statistically higher than during the convalescence stage (p<0.05), while anti-HBc affinity during HBV infection was lower than during recovery. There were correlations among total activity, affinity, protein content of anti-HBc, and ALT, HBV-DNA (p<0.05). CONCLUSIONS: It is potentially possible to predict the status of HBV infection by measuring total activity, protein content and affinity of anti-HBc.


Assuntos
Anticorpos Anti-Hepatite B/sangue , Anticorpos Anti-Hepatite B/imunologia , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Hepatite B/imunologia , Adulto , Alanina Transaminase/sangue , Afinidade de Anticorpos , DNA Viral/sangue , Feminino , Anticorpos Anti-Hepatite B/química , Humanos , Imunoensaio/métodos , Estudos Longitudinais , Masculino , Pessoa de Meia-Idade , Soro/imunologia , Carga Viral
14.
J Am Chem Soc ; 133(10): 3246-8, 2011 Mar 16.
Artigo em Inglês | MEDLINE | ID: mdl-21341767

RESUMO

Infectious hepatitis B virus (HBV), namely Dane particles (DPs), consists of a core nucleocapsid including genome DNA covered with an envelope of hepatitis B surface antigen (HBsAg). We report the synthesis, structure, and HBV-trapping capability of multilayered protein nanotubes having an anti-HBsAg antibody (HBsAb) layer as an internal wall. The nanotubes were prepared using an alternating layer-by-layer assembly of human serum albumin (HSA) and oppositely charged poly-L-arginine (PLA) into a nanoporous polycarbonate (PC) membrane (pore size, 400 nm), followed by depositions of poly-L-glutamic acid (PLG) and HBsAb. Subsequent dissolution of the PC template yielded (PLA/HSA)(2)PLA/PLG/HBsAb nanotubes (AbNTs). The SEM measurements revealed the formation of uniform hollow cylinders with a 414 ± 16 nm outer diameter and 59 ± 4 nm wall thickness. In an aqueous medium, the swelled nanotubes captured noninfectious spherical small particles of HBsAg (SPs); the binding constant was 3.5 × 10(7) M(-1). Surprisingly, the amount of genome DNA in the HBV solution (HBsAg-positive plasma or DP-rich solution) decreased dramatically after incubation with the AbNTs (-3.9 log order), which implies that the infectious DPs were completely entrapped into the one-dimensional pore space of the AbNTs.


Assuntos
Anticorpos Anti-Hepatite B/química , Vírus da Hepatite B/isolamento & purificação , Nanotubos/química , Albumina Sérica/química , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Vírus da Hepatite B/imunologia , Humanos , Albumina Sérica/imunologia
15.
J Biomed Nanotechnol ; 7(6): 776-81, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-22416576

RESUMO

Herein we reported a new type of silicon dioxide wrapped magnetic nanoparticles-labeled lateral flow strip for detection of HBs antigen in sera. The SiO2 wrapped Fe3O4 nanocomposites were prepared and characterized by HR-TEM, FTIR and magnetometer. As-prepared nanocomposites were used to label anti-HBV surface monoclonal antibody, the lateral flow strips were constructed, and 100 specimens of sera were collected and tested. Results showed that the prepared SiO2 wrapped Fe3O4 nanocomposites were shell/core structure, well dispersed, with the size of 25 nm in diameter, the thickness of the shell was about 3 nm, their magnetic saturation intensity was 44.3 meu g(-1). Clinical sera specimens test results showed that the prepared lateral flow strips were with the detection limitation of 5 pg/mL by naked eye observation, and 0.1 pg/mL by CCD reader or MAR Analyzer, specificity was 100%. In conclusion, one kind of silicon dioxide wrapped magnetic nanoparticles-labeled lateral flow strip for ultrasensitive detection of HBs antigen was successfully developed, its ease of use, sensitiveness and low-cost make it well-suited for population-based on-the-site hepatitis B screening.


Assuntos
Antígenos de Superfície da Hepatite B/sangue , Hepatite B/diagnóstico , Nanopartículas de Magnetita/química , Nanocompostos/química , Kit de Reagentes para Diagnóstico , Dióxido de Silício/química , Anticorpos Monoclonais/química , Hepatite B/sangue , Hepatite B/imunologia , Anticorpos Anti-Hepatite B/química , Humanos , Tamanho da Partícula , Sensibilidade e Especificidade
16.
Biochem Biophys Res Commun ; 396(2): 231-7, 2010 May 28.
Artigo em Inglês | MEDLINE | ID: mdl-20399745

RESUMO

We previously constructed a humanized antibody, HuS10, by grafting the complementarity-determining regions (CDRs) of a parental murine monoclonal antibody into the homologous human antibody sequences. This process is termed CDR grafting. Some residues that were thought to affect the CDR loops and stabilize the structure of the variable regions were retained in the framework region. HuS10 exhibited in vivo virus-neutralizing activity, but its murine content had the potential to elicit immune responses in patients. In this study, to minimize the immunogenic potential of HuS10, we replaced 17 mouse residues in HuS10 with the comparable human residues using specificity-determining residue (SDR)-grafting and de-immunization methods. The resultant humanized antibody, HzS-III, had the same affinity and epitope specificity as HuS10 and had reduced immunogenic potential, as assessed by T-cell epitope analysis. Thus, SDR grafting in combination with de-immunization may be a useful strategy for minimizing the immunogenicity of humanized antibodies. In addition, HzS-III may be a good candidate for immunoprophylaxis of HBV infection.


Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Anti-Hepatite B/imunologia , Antígenos de Superfície da Hepatite B/imunologia , Hepatite B/imunologia , Sequência de Aminoácidos , Animais , Anticorpos Monoclonais/química , Anticorpos Monoclonais/genética , Afinidade de Anticorpos , Mapeamento de Epitopos , Epitopos de Linfócito T/química , Epitopos de Linfócito T/genética , Epitopos de Linfócito T/imunologia , Hepatite B/prevenção & controle , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/genética , Humanos , Camundongos , Dados de Sequência Molecular , Testes de Neutralização , Estrutura Secundária de Proteína
17.
Liver Transpl ; 15(10): 1343-50, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19790164

RESUMO

Liver transplantation using grafts from donors with antibody against hepatitis B core antigen (anti-HBc) increases the recipients' risk of developing hepatitis B virus (HBV) infection post-transplantation. Our aim was to assess whether using such grafts was associated with reduced posttransplantation survival and whether this association depended on recipients' prior exposure to HBV on the basis of their pretransplantation serological patterns. Data were derived from the United Network for Organ Sharing on adult, cadaveric, first-time liver transplants performed between 1994 and 2006. Among recipients who did not have HBV infection before transplantation, those with anti-HBc-positive donors had significantly worse unadjusted posttransplantation patient survival than recipients with anti-HBc-negative donors [hazard ratio, 1.35; 95% confidence interval (CI), 1.21-1.50]. However, after adjustments for other predictors of posttransplantation survival, including donor age, donor race, and recipient underlying liver diseases, patient survival was not significantly different between the 2 groups (hazard ratio, 1.09; 95% CI, 0.97-1.24). Among recipients without antibody against hepatitis B surface antigen (anti-HBs), use of anti-HBc-positive donor grafts was associated with a trend toward worse survival (adjusted hazard ratio, 1.18; 95% CI, 0.95-1.46), whereas no such trend was observed among recipients positive for anti-HBs. In conclusion, in patients without HBV infection before transplantation, using anti-HBc-positive donors was not independently associated with worse posttransplantation survival. Matching these donors to recipients with anti-HBs pre-transplantation may be especially safe.


Assuntos
Anticorpos Anti-Hepatite B/química , Antígenos do Núcleo do Vírus da Hepatite B/imunologia , Hepatite B/virologia , Falência Hepática/terapia , Transplante de Fígado/métodos , Adulto , Estudos de Coortes , Feminino , Hepatite B/complicações , Hepatite B/mortalidade , Humanos , Falência Hepática/complicações , Falência Hepática/mortalidade , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Doadores de Tecidos , Resultado do Tratamento
18.
Vaccine ; 27(17): 2356-66, 2009 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-19428851

RESUMO

We had earlier reported the construction and characterization of a high affinity recombinant scFv generated from a potential neutralizing mouse monoclonal antibody against the Hepatitis B surface antigen. In this report we describe the humanization of this scFv by grafting its antigen binding site onto framework of the human consensus sequence of highest similarity. We have used molecular modeling to alter not only the clearly permissible residues but also several minimal positional template and V(H)/V(L) interface residues. The humanized scFv retains the binding characteristic of the mouse monoclonal even under conditions that usually destabilize antigen antibody interactions. This high affinity humanized scFv provides a basis for the development of prophylactic/therapeutic molecules.


Assuntos
Afinidade de Anticorpos , Sequência Consenso/imunologia , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/imunologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Anticorpos Monoclonais/biossíntese , Anticorpos Monoclonais/química , Anticorpos Monoclonais/imunologia , Especificidade de Anticorpos , Anticorpos Anti-Hepatite B/biossíntese , Humanos , Região Variável de Imunoglobulina/genética , Região Variável de Imunoglobulina/imunologia , Técnicas Imunológicas , Camundongos , Modelos Imunológicos , Dados de Sequência Molecular , Proteínas Recombinantes de Fusão/biossíntese
19.
Biosens Bioelectron ; 24(9): 2878-84, 2009 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-19303282

RESUMO

Hepatitis B surface antibody (HBsAb) imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) (PHEMAT) film on the surface plasmon resonance (SPR) sensor chip was prepared for diagnosis of HBsAb in human serum. Gold SPR chip surface was modified with allyl mercaptane and, then, HBsAb-imprinted PHEMAT film was formed on the chip surface. Surface characterization of the non-modified, allyl mercaptane modified and HBsAb-imprinted PHEMAT SPR chips were investigated with contact angle, atomic force microscopy (AFM). Kinetic studies were performed using HBsAb positive human serum. In order to determine the kinetic and binding constants, Scatchard, Langmuir, Freundlich and Langmuir-Freundlich models were applied to experimental data. Scatchard curve shows that HBsAb imprinted SPR chip has some surface heterogeneity, SPR chip obeyed the Langmuir adsorption model. The maximum detection limit was 208.2 mIU/mL. K(A) and K(D) values are 0.015 mIU/mL and 66.0 mL/mIU, respectively. Control experiments of the SPR chip were performed using non-immunized, HBsAb negative serum. The control experiment results show that SPR chip does not give any noticeable response to HBsAb negative serum.


Assuntos
Anticorpos Anti-Hepatite B/sangue , Hepatite B/diagnóstico , Hepatite B/imunologia , Poli-Hidroxietil Metacrilato/análogos & derivados , Ressonância de Plasmônio de Superfície/instrumentação , Tirosina/análogos & derivados , Adsorção , Ouro/química , Hepatite B/sangue , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/imunologia , Humanos , Cinética , Microscopia de Força Atômica , Modelos Químicos , Poli-Hidroxietil Metacrilato/síntese química , Poli-Hidroxietil Metacrilato/química , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/métodos , Propriedades de Superfície , Tirosina/síntese química , Tirosina/química
20.
Artigo em Inglês | MEDLINE | ID: mdl-19117814

RESUMO

Hepatitis B surface antibody imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) particles were prepared for the purification of hepatitis B surface antibody from human plasma. N-methacryloyl-L-tyrosine methyl ester was chosen as a complexing agent for hepatitis B surface antibodies. Hepatitis B surface antibody imprinted poly(hydroxyethyl methacrylate-N-methacryloyl-L-tyrosine methyl ester) particles were characterized by surface area measurements, swelling test, scanning electron microscopy, elemental analysis, and Fourier transform infrared spectroscopy. Ethylene glycol (1.0M) was used as desorption agent. Adsorption studies were performed from hepatitis B surface antibody and anti-hepatitis A antibody positive human plasma. Effects of antibody concentration, contact time, N-methacryloyl-L-tyrosine methyl ester content and temperature on the adsorption capacity were investigated. The amount of hepatitis B surface antibody adsorbed per unit mass increased with increasing hepatitis B surface antibody concentration, then reached saturation. Maximum hepatitis B surface antibody adsorption amount was 21.4 mIU/mg. Adsorption process reached the equilibrium in 60 min. Competitive adsorption of hepatitis B surface antibody, total anti-hepatitis A antibody and total immunoglobulin E was investigated for showing the selectivity. Hepatitis B surface antibody-imprinted particles could adsorb hepatitis B surface antibody 18.3 times more than anti-hepatitis A antibody and 2.2 times more than immunoglobulin E. It can be concluded that hepatitis B surface antibody-imprinted particles have significant selectivity for hepatitis B surface antibody.


Assuntos
Anticorpos Anti-Hepatite B/isolamento & purificação , Antígenos de Superfície da Hepatite B/imunologia , Metacrilatos/metabolismo , Impressão Molecular/métodos , Tirosina/metabolismo , Adsorção , Anticorpos Anti-Hepatite A/química , Anticorpos Anti-Hepatite A/isolamento & purificação , Anticorpos Anti-Hepatite B/química , Anticorpos Anti-Hepatite B/metabolismo , Humanos , Imunoglobulina E/química , Imunoglobulina E/isolamento & purificação , Cinética , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Propriedades de Superfície , Fatores de Tempo , Tirosina/análogos & derivados
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