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G R Dreesman

Publications and source records attributed to G R Dreesman.

126 records · Page 7Linked to original sources
PubMed1972

Production of potent anti-Australia antigen sera of high specificity and sensitivity in goats.

Potent antisera of high specificity and sensitivity were produced, in goats, to purified Australia antigen (Au). The antigen was prepared by one of three methods: (i) pelleting, low pH treatment, isopycnic centrifugation two times in CsCl, and rate zonal centrifugation in sucrose; (ii) same as procedure i, with the exception of the low pH treatment; or (iii) twice banding in CsCl by using a BXIV batch-type zonal centrifuge rotor with subsequent preparative Pevikon electrophoresis. The goat anti-Au sera contained high levels of precipitating antibody as tested by immunodiffusion in agar gel and discontinuous counterimmunoelectrophoresis (DCIE) as well as specific complement-fixing antibody and could be used for routine screening of sera for Au without prior adsorption with Au-negative normal human serum (NHS). Identification of 66 of 70 positive specimens (94.3%) in a panel of 98 coded sera (49 duplicates) with 100% reproducibility was made by using one of the goat anti-Au sera at a dilution of 1:16 in the DCIE method. No false positives were recorded. Low levels of antibody against NHS components were effectively removed by a single adsorption with glutaraldehyde cross-linked NHS.

Adsorption↗
PubMed1972

Biophysical and biochemical heterogeneity of purified hepatitis B antigen.

Hepatitis B antigen of the D (a+, d+, y-) subtype was purified from plasma of apparently healthy persons and from hepatitis patients. The original samples contained 20- and 42-nm particles and tubular forms (20-nm diameter). Ultracentrifugation during the purification procedure yielded pellets which were then treated at pH 2.4. Both the large, 42-nm Dane particles and the tubular forms were lost during the acid treatment of the pelleted particles, yielding a preparation containing a mixture of particles approximately 20 and 25 nm in diameter. This difference in size was substantiated in that two distinct molecular weights were calculated from high-speed equilibrium data, 3.6 x 10(6) and 4.5 x 10(6). Further heterogeneity was observed in that hepatitis B antigenic activity was present in purified particles with an isoelectric pH of 4.0 and also in those with a pH of 4.4. No significant differences were observed in the gross amino acid composition of purified antigen obtained from plasma of three different persons. (125)I-labeled, purified antigen was found to contain six distinct polypeptides with molecular weights ranging from 10,000 to 39,000.

Amino Acids↗
PubMedDate not supplied

Long-term sequelae of non-A, non-B hepatitis in experimentally infected chimpanzees.

We have observed the development of long-term sequelae in four cases of experimentally induced non-A, non-B (NANB) hepatitis in chimpanzees. These sequelae were characterized by the following manifestations: nonprotection against challenge with autologous infectious plasma following acute disease and subtle histopathological alterations typical of long-lasting viral hepatitis. These manifestations were observed in animals infected with either of two human inocula. Whether or not these inocula represent sources of single or multiple etiologic agents is not known. However, our studies suggest that these inocula share at least one common etiologic agent. Further, these results may represent an atypical chronology of convalescence from viral hepatitis infection. For example, the convalescent stage of a type B hepatitis infection may be expected to occur within 6 to 8 months following exposure, whereas true convalescence in NANB hepatitis may be protracted over several months to several years. Thus, future efforts to identify the causative agent(s) of NANB hepatitis, and efforts to define the immune response in NANB, must take into consideration these studies.

Alanine Transaminase↗
PubMedDate not supplied

Monoclonal antibodies of hybridomas.

Among the most prominent biological advances of this century, the hybridoma technology stands out as providing the best tool for the analysis of complex antigens of pathogens and tumor cells. This technology will play a major role in the immunodiagnosis and treatment of infectious and malignant diseases. This review focuses on the most recent developments (1980-1981), with emphasis on human immunology.

Adult↗
PubMedDate not supplied

Biophysical and biochemical properties of purified preparations of hepatitis B surface antigen (HBs Ag).

Two antigenically distinct subtypes, adw and ayw, of hepatitis B surface antigen (HBs Ag), have been purified from the plasma of anicteric hepatitis patients. Biophysical studies of these purified preparations revealed considerable heterogeneity in their overall surface charge, morphology and molecular weights. Chemical studies revealed that the composition of the particles is complex in that four to six different polypeptides and three glycoproteins were identified. In addition, cholesterol, three polar lipids, and two glycolipids were detected in purified HBs Ag preparations. Antisera, prepared in guinea pigs to individual polypeptides derived from HBs Ag subtypes adw and ayw, reacted with both the group- and type-specific antigenic determinants associated with the intact particles. The potential of these purified preparations of HBs Ag and of the individual subunits derived from them as possible vaccines is discussed. Specific antipolypeptide sera will be utilized to determine whether HBs Ag components are synthesized as specific viral products or are composed of components of modified host-cell molecules.

Amino Acids↗
PubMedDate not supplied

Endogenous DNA polymerase-positive core particles from hepatitis-infected hepatocytes.

The purification is described of liver-derived hepatitis B core antigen (HBc Ag) from human hepatocytes demonstrating only intranuclear particles by electron microscopy. The purified preparation contained 5 x 10(11) particles per ml. The particles were mono-dispersed and relatively free of background material. DNA-dependent polymerase activity was present and had greater activity than an equal number of cores derived from Dane particles isolated from plasma. Specificity of the polymerase reaction was confirmed by precipitation of the activity with specific anti-HBc antiserum. A proportion of the liver-derived core particles was nonreactive for DNA polymerase activity. The polymerase-positive population of particles had a larger size than the polymerase-negative population of liver-derived cores as evidenced by gel filtration in Sepharose 4B.

DNA-Directed DNA Polymerase↗