Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0019163 (hepatitis B)
 38,309 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In this solid-phase two-site enzyme immunoassay for hepatitis B surface antigen (HBsAg), three monoclonal anti-HBs are used: 5D3 (IgM) is immobilized on plastic beads; 5C3 (IgG2a) and 5C 11 (IgG1), labeled with biotin, are used as the first conjugate. Horseradish peroxidase covalently linked to avidin is the second conjugate. First, serum or plasma is incubated with the antibody-coated bead and biotin-labeled antibodies, simultaneously, at 45 degrees C for 1 h ("stat" procedure), 3 h ("standard" procedure), or 18 h ("overnight" procedure), during which HBsAg forms a complex with the solid-phase antibody and the biotinylated antibodies. The enzyme-conjugated avidin is then bound to the biotin on the antigen-antibody complex at 45 degrees C for 15 min ("stat") or 30 min (standard and overnight procedures). The beads are incubated with enzyme-substrate solution (H2O2 and o-phenylenediamine). Color developed is measured at 492 nm. All procedures satisfied third-generation HBsAg tests required by the FDA Office of Biologics, being sensitive both to ad and ay subtypes in subnanogram amounts. The assay is reactive with adw2, adw4, adr, ayw2, ayw3, and ayr subtypes and can detect viral determinants in HBsAg-anti-HBs immune complex form. Thus it provides a sensitive, simple, and reproducible alternative to radioimmunoassay.
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PMID:A monoclonal-antibody enzyme immunoassay for detection of hepatitis B surface antigen with use of a biotin-avidin system. 388 Dec

Cytoplasmic and cell membrane associated hepatitis B core antigen (HBcAg) were found to be more widespread within infected liver using indirect immunofluorescence on frozen sections than with the widely used direct immunofluorescence method. Fixation of frozen sections with carbon tetrachloride improved tissue histology without reducing the sensitivity of antigen detection. In tissue blocks fixed with formalin or ethanol-acetic acid, detection of HBcAg was reduced in comparison with frozen sections, and many cells containing low concentrations of (usually cytoplasmic and membranous) HBcAg could not be identified even using indirect immunofluorescence or peroxidase-antiperoxidase reactions. In contrast, intracellular hepatitis B surface antigen (HBsAg) was well detected in fixed sections, but membrane associated HBsAg was not detectable after fixation.
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PMID:Widespread presence of cytoplasmic HBcAg in hepatitis B infected liver detected by improved immunochemical methods. 388 5

National Institute of Preventive Medicine (NIPM) has succeeded in the development of an enzyme immunoassay (EIA) kit for detection of hepatitis B surface antigen. The sandwich principle was used for the test. Guinea pig anti-HBs IgG was used for coating microtiter plates and Horseradish peroxidase was conjugated with goat specific anti-HBs. Its stability is longer than 4 months. The lowest detectable dose is 0.7 ng/ml or better for subtype ad of HBsAg tested with Hepatitis Sensitivity Panel, Bureau of Drug and Food, Department of Health. The regression curve was determined by testing 66 samples with Auszyme II (EIA Kit. Abbott Lab.) and NIPM Kit, while Auszyme II used as a reference kit. The two EIA kits correlated well with a coefficient of determination (r2) of 0.86. Evaluation on 1,157 patients' and officers' serum samples in Tri-Service General Hospital showed that the positive rate was 24.7% (286/1,157) by RIA (Clinical Assays, Travenol Lab., USA) and that of NIPM EIA Kit was 24.4% (282/1,157). There was no statistical significance in terms of positive rate (p greater than 0.05). The positive rates of 534 blood donors are 22.1% (118/534) and 21.9% (117/534) respectively. Another evaluation on 974 serum samples in National Taiwan University Hospital showed that the positive rate was 27.2% (265/974) by Ausria II-125 (RIA. Abbott Lab.) and that of NIPM EIA Kit was 27.4% (267/974). The undetectable rate and false positive rate of NIPM EIA Kit were 0.41% (4/974) and 0.62% (6/974) respectively. In comparison with four other kind of commercial EIA Kits, the results of NIPM EIA Kit were satisfactory also. We have scaled up the reagent preparations for the kit, except the antibody coated microtiter plate preparation. At the end of March 1985 we will supply 850 EIA kits for the Development Center for Biotechnology for their hepatitis B vaccine production program.
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PMID:[Clinical evaluation of a domestically prepared enzyme immunoassay kit for the detection of hepatitis B surface antigen]. 389 43

Hepatitis B virus (HBV) core antigen (HBcAg) detected by the peroxidase-antiperoxidase technique was present in the nucleus and cytoplasm of some infected hepatocytes but only in the cytoplasm of other hepatocytes. When cells expressing HBcAg were examined by in situ hybridization for the presence of HBV DNA, the intracellular level of cytoplasmic HBV replicative intermediate DNA correlated with the level of cytoplasmic HBcAg, but not with the presence or absence of nuclear HBcAg. This suggests that nuclear HBcAg may not be directly involved in hepadnavirus replication.
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PMID:Cytoplasmic (but not nuclear) hepatitis B virus (HBV) core antigen reflects HBV DNA synthesis at the level of the infected hepatocyte. 390 90

A new capture enzyme immunoassay for the determination of immunoglobulin M (IgM) antibodies against hepatitis B core antigen (HBcAg) is described. Core antigen produced in Escherichia coli was labeled with biotin and subsequently detected by an avidin-biotin-peroxidase complex. The biotin-labeled core antigen was effective at concentrations as low as 20 ng/ml. Of 561 serum samples from different groups of patients that were tested, 465 samples were negative for other hepatitis B virus markers and also for anti-HBcAg IgM. Sera from the early stages of hepatitis B infection had high levels of anti-HBcAg IgM, and a clear correlation with the acuteness of the disease was observed in 45 follow-up sera from 23 patients with acute or recent hepatitis B. Sera from 21 patients with past hepatitis B were all negative for anti-HBcAg IgM. Twenty serum samples from chronic carriers of hepatitis B surface antigen showed slightly elevated antibody levels for anti-HBcAg IgM. Ten sera which were positive for anti-HBcAg IgG antibodies and had high levels of rheumatoid factor were negative for anti-HBcAg IgM.
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PMID:Determination of immunoglobulin M antibodies for hepatitis B core antigen with a capture enzyme immunoassay and biotin-labeled core antigen produced in Escherichia coli. 390 76

A sandwich ELISA for hepatitis B virus surface antigen (HBsAg) was developed using monoclonal anti-HBs for the solid phase and horse-radish peroxidase labelled sheep anti-HBs. The sensitivity was approx. 0.3 U/ml HBsAg, in the standard test procedure, comprising two incubation steps of 1 h at 37 degrees C, or in a shortened procedure comprising two incubation steps of 30 min at 50 degrees C. A slightly reduced sensitivity (approx. 0.5 U/ml) was obtained when the two incubations were combined in a one-step incubation for 1 h at 37 degrees C. All three procedures were completed by an incubation for 30 min at room temperature with peroxide and tetra-methylbenzidine. The number of false positives obtained when donor sera were screened was below 0.5%. False positive reactions occurred more frequently, but still to a limited extent, when previously selected sera containing rheumatoid factor or other possibly interfering factors were tested with the standard procedure. Most sera containing factors that interfere with a commercial ELISA for HBsAg using sheep anti-HBs coated plates, were negative. Rheumatoid factor positive sera seldom gave false positive results. The lower detection limit became approx. 0.1 U/ml when the cut-off was reduced, while the number of false positives in a donor population only increased to 1.5%. The results obtained with reagents from four different batches indicate a stability of up to 4 wk at 37 degrees C and for at least 26 wk at 4 degrees C.
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PMID:Improved ELISA for the detection of HBsAg. 399 41

An enzyme-linked immunosorbent assay (ELISA) was developed for the detection and quantitation of antibodies (anti-HBs) to the surface antigen of the hepatitis B virus (HBsAg). The ELISA uses HBsAg as the solid phase, and, after conjugation to horseradish peroxidase, also as the conjugate. Conditions for this assay were optimized and a rapid (1.5 hours) ELISA has evolved which works very satisfactorily for the large-scale screening of donated blood. We have used this ELISA to examine donated blood in Natal and concluded that we cannot initiate a programme of anti-HBs supplementation of parenteral blood products without hyperimmunization and plasmapheresis of selected, voluntary donors.
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PMID:Safer blood--supplementation of blood products with anti-HBs. 403 90

The localization of hepatitis B antigen (HB Ag) and the nature of the virus-like particles in hepatocytes of patients with HB antigenemia are controversial. In many reports, numerous virus-like particles have been demonstrated in hepatocytic nuclei; the few reported in the cytoplasm are insufficient in number to explain the intense cytoplasmic fluorescence after staining with fluoresceinated antibody to HB Ag (HB Ab). We found numerous tubular and circular structures, measuring 20 to 30 nm in diameter, in the cisternae of the excess smooth endoplasmic reticulum (ER) of varying numbers of hepatocytes in 13 of 16 HB Ag carriers and in 4 of 9 patients with HB Ag-positive chronic hepatitis corresponding to cytoplasmic HB Ag-specific fluorescence. Direct immunoelectronmicroscopy using peroxidase-labeled HB Ab revealed that the intracisternal bodies and the surrounding membranes contain HB antigenic determinants. These bodies are an ultrastructural correlate of cytoplasmic HB Ag. It is suggested that they are virally coded coat material rather than the mature hepatitis B virus or its core.
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PMID:Electron microscopy and immunoelectronmicroscopy of cytoplasmic hepatitis B antigen in hepatocytes. 413 80

A case is reported in which non-A, non-B posttransfusion hepatitis was followed serially by chronic persistent hepatitis, chronic active hepatitis, and liver cirrhosis that finally developed into hepatocellular carcinoma. The patient died after a 19-year clinical course. During the last 8 years, repeated attempts to identify serum hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen were consistently negative. Liver biopsy was performed five times during the clinical course, and at autopsy, liver tissue was obtained from four different nontumor regions. These specimens were investigated by a peroxidase immunoenzyme method which failed to detect hepatitis B surface antigen and hepatitis B core antigen. Non-A, non-B posttransfusion hepatitis may become chronic and sometimes may advance to hepatocellular carcinoma.
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PMID:Hepatocellular carcinoma after non-A, non-B posttransfusion hepatitis. 609 43

In the process of establishing the specificity of direct immunoperoxidase staining of liver tissue for hepatitis B surface antigen (HBsAg), an affinity of free horseradish peroxidase (HRP) for HBsAg in hepatocytes (ground-glass cells) was found. Of 95 patients, the horseradish peroxidase reaction was only positive in the livers of the 35 who were chronically HBsAg seropositive and not in the livers from 60 control patients with alcoholic cirrhosis who were HBsAg seronegative. Comparison studies using the orcein technic and immunoperoxidase methods confirmed the observation that both free horseradish peroxidase (not conjugated to an antibody) and HRP conjugated to an antibody unrelated to HBsAg had an affinity to the cytoplasm of hepatocytes containing HBsAg. The precise nature of this affinity is not known, but it is probably due to a reaction between an activated carbohydrate moiety of horseradish peroxidase and the free amino group of HBsAG.
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PMID:Nonimmunologic binding of horseradish peroxidase to hepatitis B surface antigen. A possible source of error in immunohistochemistry. 615 65


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