Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 52
Filtrar
1.
J Phys Chem Lett ; 12(5): 1438-1442, 2021 Feb 11.
Artículo en Inglés | MEDLINE | ID: mdl-33523655

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/química , SARS-CoV-2/química , Secuencia de Aminoácidos , Enzima Convertidora de Angiotensina 2/química , Sitios de Unión , Humanos , Fragmentos de Inmunoglobulinas/química , Simulación de Dinámica Molecular , Péptidos/química , Unión Proteica , Conformación Proteica , Anticuerpos de Cadena Única/química , Termodinámica
2.
J Immunol Methods ; 458: 26-32, 2018 07.
Artículo en Inglés | MEDLINE | ID: mdl-29654816

RESUMEN

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.


Asunto(s)
Técnicas Biosensibles/instrumentación , Glucemia/análisis , Antígenos de Superficie de la Hepatitis B/aislamiento & purificación , Virus de la Hepatitis B/aislamiento & purificación , Hepatitis B/diagnóstico , Anticuerpos Inmovilizados/química , Anticuerpos Inmovilizados/inmunología , Técnicas Biosensibles/economía , Técnicas Biosensibles/métodos , Glucemia/metabolismo , Ensayo de Inmunoadsorción Enzimática/economía , Ensayo de Inmunoadsorción Enzimática/instrumentación , Ensayo de Inmunoadsorción Enzimática/métodos , Epítopos/inmunología , Glucano 1,4-alfa-Glucosidasa/química , Glucano 1,4-alfa-Glucosidasa/inmunología , Glucano 1,4-alfa-Glucosidasa/metabolismo , Hepatitis B/sangre , Hepatitis B/virología , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Humanos , Límite de Detección , Nanopartículas de Magnetita/química , Juego de Reactivos para Diagnóstico/economía , Reproducibilidad de los Resultados
3.
Electrophoresis ; 39(2): 406-416, 2018 01.
Artículo en Inglés | MEDLINE | ID: mdl-28972666

RESUMEN

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.


Asunto(s)
Complejo Antígeno-Anticuerpo/sangre , Complejo Antígeno-Anticuerpo/química , Precipitación Química , Complejo Antígeno-Anticuerpo/aislamiento & purificación , Estudios de Casos y Controles , Ensayo de Inmunoadsorción Enzimática , Glicina/química , Hepatitis B/sangre , Hepatitis B/inmunología , Anticuerpos contra la Hepatitis B/sangre , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/aislamiento & purificación , Antígenos de Superficie de la Hepatitis B/sangre , Antígenos de Superficie de la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/aislamiento & purificación , Humanos , Polietilenglicoles/química
4.
J Biol Chem ; 292(40): 16760-16772, 2017 10 06.
Artículo en Inglés | MEDLINE | ID: mdl-28842495

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/inmunología , Antígenos e de la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Hepatitis B/inmunología , Proteínas Recombinantes de Fusión/inmunología , Anticuerpos de Cadena Única/inmunología , Animales , Ensayo de Inmunoadsorción Enzimática/métodos , Hepatitis B/sangre , Hepatitis B/tratamiento farmacológico , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/genética , Anticuerpos contra la Hepatitis B/uso terapéutico , Antígenos e de la Hepatitis B/sangre , Antígenos e de la Hepatitis B/química , Virus de la Hepatitis B/química , Humanos , Conejos , Proteínas Recombinantes de Fusión/química , Proteínas Recombinantes de Fusión/genética , Proteínas Recombinantes de Fusión/uso terapéutico , Anticuerpos de Cadena Única/química , Anticuerpos de Cadena Única/genética , Anticuerpos de Cadena Única/uso terapéutico
5.
World J Gastroenterol ; 22(35): 8010-6, 2016 Sep 21.
Artículo en Inglés | MEDLINE | ID: mdl-27672295

RESUMEN

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.


Asunto(s)
Antígenos de Superficie de la Hepatitis B/química , Hepatitis B/prevención & control , Fallo Hepático/cirugía , Trasplante de Hígado/métodos , Donantes de Tejidos , Antivirales/uso terapéutico , Supervivencia de Injerto , Anticuerpos contra la Hepatitis B/química , Antígenos del Núcleo de la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Humanos , Inmunoglobulinas/uso terapéutico , Lamivudine/uso terapéutico , Hígado/inmunología , Fallo Hepático/terapia , Riesgo
6.
Artículo en Ruso | MEDLINE | ID: mdl-30695452

RESUMEN

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 <

Asunto(s)
Anticuerpos contra la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B/sangre , Inmunoglobulinas/química , Animales , Pollos , Ensayo de Inmunoadsorción Enzimática/métodos , Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Humanos , Ratones
7.
BMC Biotechnol ; 15: 85, 2015 Sep 15.
Artículo en Inglés | MEDLINE | ID: mdl-26370129

RESUMEN

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.


Asunto(s)
Anticuerpos Neutralizantes/inmunología , Anticuerpos contra la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Vacunas contra Hepatitis B , Poliomavirus/genética , Vacunas de Partículas Similares a Virus , Animales , Anticuerpos Neutralizantes/química , Anticuerpos Neutralizantes/genética , Células Cultivadas , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/genética , Vacunas contra Hepatitis B/química , Vacunas contra Hepatitis B/genética , Vacunas contra Hepatitis B/inmunología , Hepatocitos/citología , Hepatocitos/virología , Poliomavirus/química , Saccharomyces cerevisiae , Tupaia , Vacunas de Partículas Similares a Virus/química , Vacunas de Partículas Similares a Virus/genética , Vacunas de Partículas Similares a Virus/inmunología
8.
FEBS Lett ; 589(2): 193-200, 2015 Jan 16.
Artículo en Inglés | MEDLINE | ID: mdl-25481411

RESUMEN

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.


Asunto(s)
Complejo Antígeno-Anticuerpo , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Secuencia de Aminoácidos , Animales , Línea Celular , Epítopos de Linfocito T/inmunología , Anticuerpos contra la Hepatitis B/farmacología , Humanos , Ratones , Modelos Moleculares , Datos de Secuencia Molecular , Estructura Terciaria de Proteína , Proteínas Virales/química , Proteínas Virales/inmunología
9.
Curr Issues Mol Biol ; 16: 69-78, 2014.
Artículo en Inglés | MEDLINE | ID: mdl-24014801

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/genética , Virus de la Hepatitis B/genética , Hepatitis B/diagnóstico , Mutación , Sustitución de Aminoácidos , Asia/epidemiología , Carcinoma Hepatocelular/epidemiología , Carcinoma Hepatocelular/etiología , Carcinoma Hepatocelular/virología , Hepatitis B/complicaciones , Hepatitis B/epidemiología , Hepatitis B/virología , Antígenos de Superficie de la Hepatitis B/aislamiento & purificación , Virus de la Hepatitis B/patogenicidad , Humanos , Lactante , Neoplasias Hepáticas/epidemiología , Neoplasias Hepáticas/etiología , Neoplasias Hepáticas/virología , Tipificación Molecular/métodos , Estudios Seroepidemiológicos
10.
J Struct Biol ; 181(1): 53-60, 2013 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-23079477

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/química , Virus de la Hepatitis B/inmunología , Proteínas del Núcleo Viral/química , Proteínas del Núcleo Viral/inmunología , Especificidad de Anticuerpos , Cromatografía de Afinidad , Microscopía por Crioelectrón , Mapeo Epitopo , Hepatitis B/inmunología , Hepatitis B/virología , Virus de la Hepatitis B/ultraestructura , Humanos , Fallo Hepático Agudo/inmunología , Fallo Hepático Agudo/virología , Modelos Moleculares , Estructura Cuaternaria de Proteína , Estructura Secundaria de Proteína , Proteínas del Núcleo Viral/aislamiento & purificación
11.
J Mol Biol ; 423(1): 63-78, 2012 Oct 12.
Artículo en Inglés | MEDLINE | ID: mdl-22750730

RESUMEN

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.


Asunto(s)
Complejo Antígeno-Anticuerpo/inmunología , Epítopos/inmunología , Anticuerpos contra la Hepatitis B/inmunología , Antígenos del Núcleo de la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Secuencia de Aminoácidos , Animales , Complejo Antígeno-Anticuerpo/química , Epítopos/química , Anticuerpos contra la Hepatitis B/química , Antígenos del Núcleo de la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/inmunología , Virus de la Hepatitis B/química , Ratones , Datos de Secuencia Molecular , Conformación Proteica
12.
IET Nanobiotechnol ; 6(1): 9-15, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22423865

RESUMEN

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.


Asunto(s)
Complejo Antígeno-Anticuerpo/química , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/química , Antígenos de Superficie de la Hepatitis B/inmunología , Pinzas Ópticas , Unión Proteica
13.
J Clin Virol ; 52(4): 295-9, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21978612

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/sangre , Anticuerpos contra la Hepatitis B/inmunología , Antígenos del Núcleo de la Hepatitis B/inmunología , Hepatitis B/inmunología , Adulto , Alanina Transaminasa/sangre , Afinidad de Anticuerpos , ADN Viral/sangre , Femenino , Anticuerpos contra la Hepatitis B/química , Humanos , Inmunoensayo/métodos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Suero/inmunología , Carga Viral
14.
J Am Chem Soc ; 133(10): 3246-8, 2011 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-21341767

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/química , Virus de la Hepatitis B/aislamiento & purificación , Nanotubos/química , Albúmina Sérica/química , Anticuerpos contra la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Virus de la Hepatitis B/inmunología , Humanos , Albúmina Sérica/inmunología
15.
J Biomed Nanotechnol ; 7(6): 776-81, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22416576

RESUMEN

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.


Asunto(s)
Antígenos de Superficie de la Hepatitis B/sangre , Hepatitis B/diagnóstico , Nanopartículas de Magnetita/química , Nanocompuestos/química , Juego de Reactivos para Diagnóstico , Dióxido de Silicio/química , Anticuerpos Monoclonales/química , Hepatitis B/sangre , Hepatitis B/inmunología , Anticuerpos contra la Hepatitis B/química , Humanos , Tamaño de la Partícula , Sensibilidad y Especificidad
16.
Biochem Biophys Res Commun ; 396(2): 231-7, 2010 May 28.
Artículo en Inglés | MEDLINE | ID: mdl-20399745

RESUMEN

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.


Asunto(s)
Anticuerpos Monoclonales/inmunología , Anticuerpos contra la Hepatitis B/inmunología , Antígenos de Superficie de la Hepatitis B/inmunología , Hepatitis B/inmunología , Secuencia de Aminoácidos , Animales , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/genética , Afinidad de Anticuerpos , Mapeo Epitopo , Epítopos de Linfocito T/química , Epítopos de Linfocito T/genética , Epítopos de Linfocito T/inmunología , Hepatitis B/prevención & control , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/genética , Humanos , Ratones , Datos de Secuencia Molecular , Pruebas de Neutralización , Estructura Secundaria de Proteína
17.
Liver Transpl ; 15(10): 1343-50, 2009 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-19790164

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/química , Antígenos del Núcleo de la Hepatitis B/inmunología , Hepatitis B/virología , Fallo Hepático/terapia , Trasplante de Hígado/métodos , Adulto , Estudios de Cohortes , Femenino , Hepatitis B/complicaciones , Hepatitis B/mortalidad , Humanos , Fallo Hepático/complicaciones , Fallo Hepático/mortalidad , Masculino , Persona de Mediana Edad , Modelos de Riesgos Proporcionales , Estudios Retrospectivos , Donantes de Tejidos , Resultado del Tratamiento
18.
Vaccine ; 27(17): 2356-66, 2009 Apr 14.
Artículo en Inglés | MEDLINE | ID: mdl-19428851

RESUMEN

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.


Asunto(s)
Afinidad de Anticuerpos , Secuencia de Consenso/inmunología , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/inmunología , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Anticuerpos Monoclonales/biosíntesis , Anticuerpos Monoclonales/química , Anticuerpos Monoclonales/inmunología , Especificidad de Anticuerpos , Anticuerpos contra la Hepatitis B/biosíntesis , Humanos , Región Variable de Inmunoglobulina/genética , Región Variable de Inmunoglobulina/inmunología , Técnicas Inmunológicas , Ratones , Modelos Inmunológicos , Datos de Secuencia Molecular , Proteínas Recombinantes de Fusión/biosíntesis
19.
Biosens Bioelectron ; 24(9): 2878-84, 2009 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-19303282

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/sangre , Hepatitis B/diagnóstico , Hepatitis B/inmunología , Polihidroxietil Metacrilato/análogos & derivados , Resonancia por Plasmón de Superficie/instrumentación , Tirosina/análogos & derivados , Adsorción , Oro/química , Hepatitis B/sangre , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/inmunología , Humanos , Cinética , Microscopía de Fuerza Atómica , Modelos Químicos , Polihidroxietil Metacrilato/síntesis química , Polihidroxietil Metacrilato/química , Sensibilidad y Especificidad , Resonancia por Plasmón de Superficie/métodos , Propiedades de Superficie , Tirosina/síntesis química , Tirosina/química
20.
Artículo en Inglés | MEDLINE | ID: mdl-19117814

RESUMEN

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.


Asunto(s)
Anticuerpos contra la Hepatitis B/aislamiento & purificación , Antígenos de Superficie de la Hepatitis B/inmunología , Metacrilatos/metabolismo , Impresión Molecular/métodos , Tirosina/metabolismo , Adsorción , Anticuerpos de Hepatitis A/química , Anticuerpos de Hepatitis A/aislamiento & purificación , Anticuerpos contra la Hepatitis B/química , Anticuerpos contra la Hepatitis B/metabolismo , Humanos , Inmunoglobulina E/química , Inmunoglobulina E/aislamiento & purificación , Cinética , Microscopía Electrónica de Rastreo , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Factores de Tiempo , Tirosina/análogos & derivados
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...