I I Ionescu-Matiu

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The biotin/avidin system was incorporated into the enzyme-linked immunosorbent assay (ELISA) technique to increase the sensitivity of the standard ELISA for the detection of mouse antibody to hepatitis B surface antigen ((anti-HBs and HBsAg, respectively). Two biotin/avidin ELISA designs were studied. In both assays, 96-well polystyrene plates were coated(More)
17 monoclonal antibodies generated against purified hepatitis B surface antigen (HBsAg), subtype ayw, were characterized by solid-phase radioimmunoassays. Eleven of these antibodies had specificity against the group-specific alpha determinant of HBsAg, two demonstrated antibody activity against the w HBsAg subtype, one against human serum albumin, and three(More)
Four major polypeptides with mol. wt. of 22000, 25000, 52000 and 68000 were isolated from solubilized preparations of hepatitis type B surface antigen (HBsAg). These four populations, referred to as P22, P25, P52 and P68, respectively, were used to immunize guinea-pigs. Guinea-pigs were also inoculated with HBsAg and with purified human serum albumin(More)
Complete Freud adjuvant, aluminum gel, and liposomes were compared for their ability to enhance the immunogenicity of an intact 22-nm HBsAg particle vaccine and an HBsAg-derived polypeptide vaccine in guinea pigs. Both humoral and cell-mediated immune responses were evaluated. The greatest immune response was obtained with complete Freund adjuvant,(More)
A synthetic peptide (SP1), corresponding to the amino acid residues 122 through 137 of the major polypeptide derived from hepatitis B surface antigen (HBsAg), subtype ayw, was analyzed for the presence of the major epitopes of HBsAg. Both a cyclic form, produced by introduction of an intrachain disulfide bond, and a linear form of the peptide were(More)
A cyclic peptide containing the amino acid sequence 122 through 137 of the major hepatitis B surface antigen (HBsAg) polypeptide was synthesized. The immunogenicity of this synthetic peptide, aggregated in micelles or covalently coupled to tetanus toxoid, was assessed in mice. Antibodies against HBsAg (anti-HBs) were obtained with both preparations,(More)
Three micro solid phase immunoassays (a micro-SPRIA and two ELISA techniques) were developed and tested for the detection of anti-HBs antibodies. Two different crosslinkers (glutaraldehyde and N-succinimidyl 3-(2-pyridyldithio) propionate) were used to couple a goat anti-mouse IgG reagent to alkaline phosphatase for use as enzyme-labeled probes in the two(More)
A common human anti-hepatitis B surface antigen idiotype-anti-idiotype reaction was partially inhibited by a cyclic synthetic hepatitis B surface antigen peptide. Reduction of the intrachain disulfide bond and subsequent alkylation destroyed its inhibitory activity, suggesting that a conformation-dependent group alpha epitope was associated with this cyclic(More)