title: Preparation of europium-streptavidin in a time-resolved fluoroimmunoassay for interleukin-3.
abstract: The preparation and immunoassay performance of europium-labeled streptavidin is described. The Eu-streptavidin conjugate can serve as a general detection reagent in time-resolved fluoroimmunoassays (TRFIA). The usefulness of such a strategy has previously been demonstrated with the Eu3+ chelate 4,7-bis(chlorosulfophenyl)-1,10-phenanthroline-2,9-dicarboxylic acid (Diamandis et al. 1988). In this report the conjugation of streptavidin was accomplished with the Eu3+ chelate of N1-(p-isothiocyanatobenzyl)diethylenetriamine-N1,N3,N3(+)-tetraace tic acid, using a 50 M excess of the label. The conjugation ratio of Eu3+/streptavidin was 16. The use of the Eu-streptavidin reagent in a two-site immunometric assay to measure human recombinant interleukin-3 in human plasma, showed that the useful range of the assay was 20-25,000 pg/ml.
authors.affiliation: Department of Biopharmaceutics, Sandoz Pharma, Basel, Switzerland.
authors.forename: H P
authors.initials: HP
authors.lastname: Knopf
authors.forename: R
authors.initials: R
authors.lastname: Papoian
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry / Q000302:isolation & purification; D002614:Chelating Agents; D002850:Chromatography, Gel; D005063:Europium / Q000737:chemistry / Q000302:isolation & purification; D015200:Fluoroimmunoassay / Q000379:methods; D006801:Humans; D007377:Interleukin-3 / Q000097:blood*; D011994:Recombinant Proteins; D019809:Streptavidin
chemical_list: D001426:Bacterial Proteins; D002614:Chelating Agents; D007377:Interleukin-3; D011994:Recombinant Proteins; D005063:Europium; D019809:Streptavidin