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Query: UNIPROT:Q17RS7 (Gen)
 130,125 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Stokes radius of umpurified hepatitis B antigen (HBSAg) was determined by chromatography on a carefully calibrated Sepharose 4B column. A value of 14-2 nm was found by this procedure, contrasting with a published value of II nm for purified, pepsin-treated HBSAg. Chromatography at pH 3 appeared to reduce the Strokes radius of HBSAg to II nm. Evidence is presented to show that serum proteins adsorbed to HBSAg can be removed with pepsin or acid.
J Gen Virol 1976 Nov
PMID:Gel filtration of hepatitis B surface antigen: increased size of the native particle. 1 Dec 76

Purified [125I]-labelled 20 to 25 nm hepatitis B antigen particles were found to give low affinity immunoprecipitation reactions with antisera to several normal serum components, which were immunologically distinct from the reaction due to the classical hepatitis B antigen surface determinant. These additional antigenic determinants were acid-stable and tightly bound to the particles; they could not be released by treatment with Tween 80 or ether, but were removed by protease digestion with the preservation of particle integrity. It was not possible to distinguish whether they were due to the presence of trace amounts of partly denatured serum components, or to a weak cross-reaction with antigens present in normal serum. The implications of this finding for hepatitis B antigen and antibody detection in sensititive assays are discussed. No evidence was found for native antigenic material, present in normal serum or normal liver cells, being integral to the structure of these particles.
J Gen Virol 1975 May
PMID:Host components in hepatitis B antigen. 4 95

Additional antigenic sites, distinct from those present on spherical 20 nm diam. particles of hepatitis B surface antigen (HBsAg), are exposed on the surface of Dane particles and tubular forms of HBsAg. The immunological relationship of these sites to e-antigen, an antigen detected earlier in HBsAg-positive sera from patients with chronic hepatitis, cirrhosis or acute hepatitis but not in healthy HBsAg-carriers, was established by immune electron microscopy and affinity chromatography. These findings suggest that e-antigen may be potentially useful in active immunization against hepatitis B.
J Gen Virol 1976 Mar
PMID:Identification of additional antigenic sites on Dane particles and the tubular forms of hepatitis B surface antigen. 5 22

Immune complexes could be formed with hepatitis B Ag and anti-IgG serum after treatment of the antigen with detergent, CsCl or glycerol, but not before. It is suggested that an antigenic determinant specifically reacting with anti-IgG forms an integral part of hepatitis B Ag. This determinant is ordinarily obscured in the undamaged antigen.
J Gen Virol 1976 Feb
PMID:Hepatitis B antigen: IgG components shown by immune electron microscopy. 5 92

The sedimentation of radiolabelled 22 nm hepatitis B surface antigen particles was unaffected by treatment with either trypsin or SDS alone, but combined treatment disrupted the particulate nature of the radiolabelled material. Considerable antibody binding activity by the group-specific determinant (a) was preserved after combined SDS and trypsin treatment but was released from the bulk of the radiolabelled protein; gel filtration indicated an approximate mol. wt. of 5000 to 15000 for the released antibody binding material. This material was precipitated by concanavalin A, suggesting the presence of carbohydrate. Its serological activity was remarkably resistant to boiling and to proteolytic digestion, but was partially sensitive to treatment with 0-01 M-periodate or with mixed carbohydrases and neuraminidase, and was greatly reduced by treatment with reducing agent. These data suggest that the stability of the a determinant is due to the structure of the antibody binding site itself, rather than to involvement in the quaternary structure of the particle, and that intact disulphide bonds and carbohydrate, closely related to the antibody binding site, are necessary for the full expression of serological acitivity.
J Gen Virol 1976 Oct
PMID:Tryptic cleavage of antibody binding sites from hepatitis B surface antigen particles. 6 23

The nucleocapsid of Dane particles (= hepatitis B core antigen; HBcAg) was isolated from human sera either positive or negative for e-antigen (HBeAg)--an apparent marker for the level of infectious hepatitis B virus in serum. HBcAg from the HBeAg-positive serum pool consisted of two distinct populations of particles, one with a buoyant density (d) of 1.358 g/ml and a sedimentation coefficient (S20, w) of approximately 110, and another with d = 1.25 to 1.30 g/ml and S20, w approximately 70. Only the latter type of particles was isolated from an HBeAg-negative serum pool. HBcAg was labelled with 125I-p-hydroxyphenylpropionic acid N-hydroxysuccinimide ester, dissociated and analysed by polyacrylamide gel electrophoresis. One major and one minor polypeptide with apparent mol. wt. of 16000 +/- 500 and 68000, respectively, were detected. Another component have the properties of a glycolipid with a mol. wt. in the order of 10(3) was observed. After isoelectric focusing, HBcAg was recovered in fractions with a pH between 4.0 and 5.8, suggesting heterogeneity in isoelectric points.
J Gen Virol 1978 Apr
PMID:Some properties of hepatitis B core antigen isolated from serum of infected humans. 7 70

Immunoprecipitates obtained by reacting Dane particle cores with human antibodies to hepatitis B core antigen (HBcAg) were chromatographed on columns of Sepharose 4B CL using 3 M-NaSCN as eluant. An antigen having the size and immunological specificity of monomeric e-antigen (HBeAg) was separated from HBcAg by this method. Antisera from animals immunized with HBcAg or HBeAg reacted not only with the antigen used for immunization but also with HBeAg and HBcAg, respectively. This indicates that HBeAg determinants are associated with the core of Dane particles.
J Gen Virol 1979 Mar
PMID:Association of hepatitis B e-antigen (HBeAg) determinants with the core of Dane particles. 8 91

Three glycoproteins of intact hepatitis B surface antigen (HBsAg) with mol. wt. of 32 000, 30 000 and 28 000 respectively were identified by reaction with 125I-concanavalin A (Con A) after separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE). The antigen was effectively disrupted with Triton X-100 to produce a structure with a sedimentation coefficient of 3.9S. Affinity chromatography of disrupted HBsAg using concanavalin A-Sepharose 4B (Con A-Sepharose) resulted in two fractions. The first contained material which did not bind to the lectin and consisted of a single polypeptide of mol. wt. 64 000. Further studies revealed this component to be serologically identical to serum albumin and to lack any affinity for antibody to HBsAg. A comparison of the tryptic peptide map of this polypeptide with that of purified serum albumin demonstrated identical amino-acid sequences. The second fraction contained material which bound to Con A and contained two polypeptides with mol. wt. of 28000 and 23000 respectively. HBsAg reactivity was associated with this fraction. This procedure allows the prepartion of HBsAg sub-units in milligram quantities for further immunological studies.
J Gen Virol 1979 Sep
PMID:Analysis of hepatitis B surface antigen components solubilized with Triton X-100. 9 17

A radioimmunoassay for hepatitis B e-antigen (HBeAg) is described. Polystyrene beads coated with IgG prepared from a human serum containing antibodies to HBeAg (anti-HBe) and anti-HBe IgG labelled with 125I-p-hydroxyphenylpropionic acid N-hydroxysuccinimide ester were used in the test. The radioimmunoassay was approximately 1,000-fold more sensitive than immunodiffusion. At least a transient presence of HBeAg in serum appears to be a common feature of infections by hepatitis B virus. The radioimmunoassay was instrumental in establishing conditions for identification of apparently free monomeric HBeAg. The HBeAg has an approximate mol. wt.of 35,000 and was recovered after isoelectric focusing in fractions with a pH between 4.25 and 4.8. Polyacrylamide gel electrophoresis revealed the presence in HBeAg of a polypeptide with an apparent mol. wt. of 17,000.
J Gen Virol 1979 Mar
PMID:Radioimmunoassay of hepatitis B e-antigen (HBeAg): identification of HBeAg not associated with immunoglobulins. 10 72

Liver tissue infected with hepatitis B virus was homogenized and nuclei were separated by centrifugation. Hepatitis B core particles were obtained from the nucleus by the digestion with pronase followed by ultracentrifugation in a sucrose density gradient. Hepatitis B core particles were then treated with sodium dodecyl sulphate and 2 mercaptoethanol and tested for hepatitis B e antigen (HBeAg) by the haemagglutination method. The antigenicity of HBeAg was clearly demonstrated in hepatitis B core particles so treated, although untreated core particles did not reveal any detectable HBeAg activity. The localization of HBeAg in hepatitis B core particles was further supported by the results of a fluorescent antibody technique. When a frozen section of the liver infected with hepatitis B virus was stained with the specific rabbit antibody against HBeAg labelled with fluorescent isothiocyanate, only nuclei of hepatocytes were stained, in a similar distribution to hepatitis B core antigen visualized by fluorescent antibody against hepatitis B core antigen in a nearby section.
J Gen Virol 1979 Mar
PMID:Demonstration of hepatitis B e antigen in hepatitis B core particles obtained from the nucleus of hepatocytes infected with hepatitis B virus. 37 95


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