title: [The use of biotin-streptavidin systems for enhancing the parameters of immunometric analysis].
abstract: The possibility of improving analytical parameters of the immunometric assay with the use of biotinylated antibodies and biotin-streptavidin complexes in comparison with the commonly known approach of direct antibody modification with 125I has been studied. Experiments have been carried out with the use of low-affinity antibodies (Kass approximately 10(9) M-1) to ferritin. The signal-to-noise ratio in the immunometric increases 2.3 times when streptavidin labeled with horse-radish peroxidase is used and 4.3 times when the preformed streptavidin + biotin-peroxidase complex is used in comparison with assay systems based on 125I-labeled antibodies. The improvement of assay parameters of immunochemical systems by means of biotin-streptavidin complexes has been found to permit the use of low-affinity antibodies as assay reagents, thus ensuring analytical parameters attaining or close to those of immunoradiometric assay systems based on high-affinity 125I-labeled antibodies (Kass approximately 10(10) M-1). As shown in this study, the following factors ensure the signal enhancement in biotin-streptoavidin systems: (a) the biotin modification of several lysin residues per IgG molecule, the optimum extent of modification being 3-4 residues per molecule; (b) mild procedure for biotinylation. In contrast to oxidative iodination, the modification of NH2 groups with biotin esters does not significantly affect their antigen-binding properties.
authors.forename: G I
authors.initials: GI
authors.lastname: Lepesheva
authors.forename: S P
authors.initials: SP
authors.lastname: Martsev
mesh_terms: D000906:Antibodies / Q000032:analysis; D000915:Antibody Affinity / Q000276:immunology; D001426:Bacterial Proteins; D001710:Biotin; D005069:Evaluation Studies as Topic; D005293:Ferritins / Q000276:immunology; D006735:Horseradish Peroxidase; D006801:Humans; D007120:Immunochemistry; D007158:Immunologic Techniques; D007202:Indicators and Reagents; D011863:Radioimmunoassay; D019809:Streptavidin
chemical_list: D000906:Antibodies; D001426:Bacterial Proteins; D007202:Indicators and Reagents; D001710:Biotin; D005293:Ferritins; D019809:Streptavidin; D006735:Horseradish Peroxidase
vernacular_title: Primenenie biotin-streptavidinovykh sistem dlia usileniia parametrov immunometricheskogo analiza.