ABSTRACT
Samples of human serum gamma-globulin with specifically bound copper or zinc cations were studied in Mancini's radial immunodiffusion test with human antibodies to IgG (H+L). The intensity of antibody binding to zinc-modified protein was 10-20% higher in comparison with the reference sample, while detection of gamma-globulin with bound copper by antibodies was 20-30% lower than in the corresponding reference sample. Comparison with the results of native gamma-globulin testing indicates limitations of Mancini's method as the quantitative assay for practical diagnosis, because under certain clinical conditions the traditional method can give over- and underestimated results.
Subject(s)
Blood Chemical Analysis/methods , Cations/metabolism , Metals/metabolism , gamma-Globulins/analysis , gamma-Globulins/metabolism , Blood Chemical Analysis/standards , Cations/chemistry , Cations/pharmacology , Copper/chemistry , Copper/metabolism , Humans , Metals/chemistry , Metals/pharmacology , Osmolar Concentration , Protein Binding , Serologic Tests/methods , Serologic Tests/standards , Zinc/chemistry , Zinc/metabolismABSTRACT
Samples of human serum gamma-globulin modified by equimolar binding of copper and zinc cations were obtained using the method of molecular ultrafiltration. Conformation characteristics of the protein were studied by UV spectrophotometry. Immunochemical study included radial immunodiffusion test, direct and sandwich enzyme immunoassays. Conformation changes in gamma-globulin caused by incorporation of solitary metal cations into the protein molecule modified presentation of antigenic determinants on the globule surface and their availability for recognition by specific antibodies. New antigenic determinants and new antigenic specificity of gamma-globulin are not formed under these conditions.
Subject(s)
Copper/metabolism , Zinc/metabolism , gamma-Globulins/metabolism , Enzyme-Linked Immunosorbent Assay , Epitopes/chemistry , Epitopes/immunology , Epitopes/metabolism , Humans , Protein Binding , Protein Conformation , Spectrophotometry, Ultraviolet , gamma-Globulins/chemistry , gamma-Globulins/immunologyABSTRACT
Specimens of human serum gamma-globulin modified by molar excess of copper and zinc cations were obtained by molecular ultrafiltration. Conformation characteristics of the protein were determined by UV spectrophotometry. Immunochemical study included radial immunodiffusion test and direct and sandwich enzyme-linked immunosorbent assay. After binding of copper and zinc, the gamma-globulin molecule underwent conformation changes modifying presentation of antigenic determinants on the globule surface and their availability for recognition by specific antibodies. The effects of copper were much more pronounced than those of zinc cations.
