DNA polymerase associated with human hepatitis B antigen

DNA polymerase activity was detected in each of eight preparations of concentrated human hepatitis B antigen (HBAg) rich in Dane particles prepared by high-speed centrifugation of antigen-positive human plasma and in none of seven control preparations prepared in the same way from HBAg-negative plasma. The incorporation of (3)H-thymidine-methyl-5'-triphosphate into DNA was dependent on four deoxyribonucleoside triphosphates and MgCl(2). Treatment of the concentrated HBAg preparations with the nonionic detergent Nonidet P-40 (NP40) more than doubled the enzyme activity. Fractionation of the concentrated HBAg preparation in sucrose density gradients after treatment with NP40 revealed that the enzyme activity appeared within the density range of Dane core antigen but at a slightly higher density than the average for core antigen. The only particles observed by electron microscopy in this region of the gradient were typical 28-nm cores, suggesting that the DNA polymerase activity was associated with a subpopulation of cores. No DNA polymerase activity was found in purified 20-nm HBAg particles. The DNA product of the reaction remained associated with the 110S core and was not susceptible to DNase digestion when associated with the core. Inhibition of the reaction by actinomycin D and daunomycin suggested that the reaction was dependent on a DNA template associated with the core.

Microtiter solid-phase radioimmunoassay for hepatitis B antigen

A micro-solid-phase radioimmunoassay (micro-SPRIA) for hepatitis B antigen (HB Ag) was developed for use with microtiter serological equipment. Radiolabeled immunoglobulin G was prepared from human and animal sera containing hepatitis B antibody (HB Ab); it was not necessary to isolate specific HB Ab by immunochemical means. A micro-SPRIA prepared with guinea pig reagents was approximately as sensitive as the AusRIA radioimmunoassay, but, like the AusRIA test, yielded false positive results. A micro-SPRIA prepared with human reagents was slightly less sensitive but did not yield false positive results. These micro-SPRIA tests offer several advantages, including conservation of reagents, adaptability to other antigen-antibody systems, ease of performance (especially when testing large numbers of specimens), and economy.

Subtyping of Hepatitis-Associated Antigen (HB Ag); Simplified Technique with Counterelectrophoresis

A simple and sensitive counterelectrophoresis technique for determining the subtype of hepatitis-associated antigen (HB Ag) in sera is described. Using monovalent antisera, or polyvalent antisera rendered monovalent by appropriate absorption, we detected a group-specific antigenic determinant, a, and two additional specificities, d and y. All HB Ag-containing sera could be subtyped as either ad or ay. The subtype appears to be determined by the viral agent, not the host, and to remain the same in affected individuals.

While the frequency of subtypes ad and ay were about the same for patients with acute hepatitis, ad was much more common in patients with chronic hepatitis. Subtype ad was also detected more frequently than ay in blood donor carriers of HB Ag. The major values of subtyping for HB Ag will probably be in the study of the epidemiology of hepatitis B and the development of optimal testing reagents for HB Ag detection.

Australia antigen: large-scale purification from human serum and biochemical studies of its proteins

Biophysical techniques are described for the large-scale isolation of Australia antigen (Au) from unit quantities of human serum by using the batch-type zonal centrifuge rotors. A three-step procedure involving isopycnic banding of the particle in CsCl density gradients and rate-zonal centrifugation on sucrose gradients resulted in a highly purified Au preparation which was used for biochemical studies of Au proteins and as immunizing antigen for the production of reagent antiserum in animals. The spherical form of Au, which was devoid of detectable nucleic acid, was composed of two major proteins (AuP1 and AuP2) and a minor protein (AuP3) of 26,000, 32,000, and 40,000 molecular weight, respectively, as determined by acrylamide gel electrophoresis. The significance of these findings to the possibility of Au subtypes is discussed.

Frequency of Antibody to Hepatitis-Associated Antigen As Measured by a New Radioimmunoassay Technique

A modification of the radioimmunoassay procedure for measuring antibody to hepatitis-associated antigen (HAA) using a double antibody precipitation method in a microtiter system is described. The test is 2,000 to 500,000 times more sensitive than complement fixation and is reproducible and specific for anti-HAA.

The frequency of anti-HAA was 14.4% in voluntary blood donors, 22.6% in commercial blood donors, 14.8% in blood bank personnel, 11.4% in laboratory personnel and 82.6% in persons given multiple transfusions.

The high frequency of anti-HAA in persons with no history of hepatitis or parenteral exposure to blood suggests that HAA-positive hepatitis is endemic in the United States and that it is transmitted by a non-parenteral route.

Cultivation of Mycoplasmas on glass

Eight Mycoplasma species of human origin were successfully cultivated on glass. Complement-fixing (CF) antigens prepared from glass-adherent mycoplasmas were potent, specific, and free from anticomplementary activity. PPLO broth medium supplemented with 1 to 5% PPLO serum fraction (bovine), 2.5% fresh yeast extract, and 1% glucose (glycolytic species) or 1% arginine (arginine-utilizing species) supported moderate to luxuriant growth of mycoplasmas on glass. The potency of CF antigens prepared from glass-adherent mycoplasmas varied with the species of Mycoplasma tested and the duration of incubation. When the potency of CF antigens prepared from glass-adherent mycoplasmas was compared with that material sedimented from the broth phase of the same culture, three patterns of growth were observed: M. hominis and M. orale type 2 grew preferentially in the broth phase; M. salivarium, M. orale types 1 and 3, M. pneumoniae, and M. lipophilum preferentially adhered to the glass; and M. fermentans was biphasic. The growth of mycoplasmas on glass provides a simple means of concentrating and purifying such organisms for immunological and biochemical studies.

Electrophoretic analysis of cell proteins of T-strain mycoplasmas isolated from man

Electrophoretic patterns of the cell proteins of 12 T-strain mycoplasmas isolated from man showed a remarkable similarity. This finding suggests that these strains are genetically closely related and supports their classification in a single species.