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Biomedical subjects

A R Neurath

Publications and source records attributed to A R Neurath.

At least 109 records · Page 6Linked to original sources
PubMed1977

Host specificity of a serum marker for hepatitis B: evidence that "e antigen" has the properties of an immunoglobulin.

A family of antigens, referred to collectively as e antigen (eAg), has been detected in sera of some individuals with liver disease who test positive for hepatitis B surface antigen. Studies on eAg partially purified by affinity chromatography on insolubilized antibodies to eAg revealed the following: (i) eAg has the physicochemical and immunologic properties of an immunoglobulin, predominantly of the IgG4 subclass, and (ii) specific antigenic sites, designated as e determinants, differentiate eAg from other immunoglobulins. We suggest that these determinants represent idiotypic determinants on antibodies that are formed in response to hepatitis B virus infection and that block the host's immune surveillance mechanisms by which virus proliferation is stopped.

Chromatography, Affinity↗
PubMed1976

Identification of additional antigenic sites on Dane particles and the tubular forms of hepatitis B surface antigen.

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.

Acute Disease↗
PubMed1976

Evidence against the postulated identity of e-antigen with DNA polymerase associated with the hepatitis B candidate virus.

Partially purified preparations of e-antigen, obtained from sera of hepatitis B antigen carriers, were chromatographed on columns of immobilized single- or double-stranded DNA or on pyran-Sepharose. e-Antigen did not adsorb to any of these columns under conditions appropriate for the retention of various nucleic acid polymerases. Therefore, e-antigen and the DNA polymerase associated with Dane particles can be regarded as distinct proteins.

Carrier State↗
PubMed1975

Thyroxine binding by hepatitis B surface antigen.

Thyroxine and triiodothyronine binding sites are present on the 20-nm spherical particles associated with hepatitis B surface antigen (HBsAg). Thyroxine-treated HBsAg has a buoyant density of 1.26 g/cm-3 in CsCl and appears under the electron microscope as a hexagonal particle with a center-to-vertex distance of 10 nm. These results provoke questions concerning the origin of thyroid hormone binding sites on HBsAg and a possible relationship between thyroid status and HBsAg antigenemia in humans.

Binding Sites, Antibody↗
PubMed1975

Sialyl residues in hepatitis B antigen: their role in determining the life span of the antigen in serum and in eliciting an immunological response.

Hepatitis B surface antigen was adsorbed to insolubilized sialic acid-specific haemagglutinin isolated from the haemolymph of Limulus polyphemus. Treatment of the antigen with Vibrio cholerae neuraminidase (EC 3.2.1.18) resulted in the release of sialic acid and in an increase of the isoelectric point from pH 4-35 (for subtype ad) or 4-9 (for subtype ay) to pH 5-45. Treated, but not untreated, antigen incorporated [14-C]-sialic acid when incubated at 37 degrees C with sialyl transferase (EC 2.4.99.1) and cytidine-5'-monophosphate-[14-C]-sialic acid. The major portion of [14-C]-sialic acid was linked to a glycoprotein with an apparent mol. wt. of 26 x 10-a. De-sialylated antigen had a drastically reduced in vivo life span in rabbit plasma and elicited a higher humoral antibody response than intact antigen (subtype ad). Antigen-stimulated proliferation of lymphocytes, measured 3 months after immunization, was observed only with cells from rabbits injected with neuraminidase-treated antigen.

Adsorption↗
PubMed1975

Hydrophobic chromatography of hepatitis B surface antigen on 1,9-diaminononane or 1,10-diaminodecane linked to agarose.

A series of omega-aminoalkyl-agarose differing in the number of carbon atoms in the alkyl chains was prepared and used for chromatography of hepatitis B surface antigen (HBSAg). HBSAg was separated from the major part of serum proteins by adsorption to columns of 1,9-diaminononane or 1,10-diaminodecane linked to agarose beads (Sepharose 4B or 2B) followed by elution with 4 M-NaSCN.

Alkanes↗
PubMed1975

Some considerations regarding active immunization with HBsAg.

Krugman has demonstrated that injection of heated serum containing HBsAg conferred some protection against subsequent challenge with live hepatitis B virus (HBV). It is likely that improved protection will result from injections for larger quantities of HBsAg. This can be readily done with purified antigen. We have carried out preliminary studies in mice to investigate the inactivation kinetics of HBsAg antigenicity and immunogenicity. Rates of inactivation of the two parameters by heat have been found to be parallel. Chimpanzees will be required to determine adequacy of inactivation procedures, and optimal dose and immunization schedule, prior to the initiation of human trials. The use of newly imported chimpanzees for this purpose may be hazardous. Of 27 chimpanzees recently tested in an exporter's compound in Sierra Leone, ten were found to circulate HBsAg and five additional had detectable anti-HBs, suggesting a high risk of hepatitis B transmission within the compound. Thus newly imported animals may be incubating HB infection, and could give rise to false positive results in inactivation trials, unless quarantined for a four to six month period prior to use. We have therefore established a laboratory for chimpanzee trials in West Africa, and plan to utilize only animals captured by trapping and held in strict isolation from the time of capture. It is unlikely that immunization against HBV will ever provide absolute immunity. Three chimpanzees who received a massive transfusion of infective plasma one year after resisting challenge with aliquots of the same plasma inoculated intraperitoneally, all developed severe hepatitis, accompanied in two cases by HBs antigenemia, despite strong anamnestic anti-HBs responses in all three animals.

Animals↗
PubMed1974

Hepatitis B antigen: antigenic sites related to human serum proteins revealed by affinity chromatography.

Hepatitis B antigen-associated particles, isolated from sera of antigen carriers, were submitted to affinity chromatography on columns of insolubilized antibodies to normal human plasma. The particles adsorbed to the immunosorbent at pH 7.2 and were subsequently eluted at pH 2.2. Exposure of the particles to 8 M urea, 5 M KI, pH 2.2, detergents, organic solvents, or proteolytic enzymes failed to prevent their subsequent adsorption to the immunosorbent. This suggests that antigenic determinants related to human plasma proteins are constituent components of hepatitis B antigen-associated particles. These determinants are distinct from the group-specific (a) and subtype-specific (d or y) sites of the hepatitis B antigen and appear to be related to antigenic specificities on prealbumin, albumin, apolipoproteins C and D, and the gamma-chain of immunoglobulin G.

Animals↗