title: Simultaneous quantitation of diphtheria and tetanus antibodies by double antigen, time-resolved fluorescence immunoassay.
abstract: A dual, double antigen, time-resolved fluorescence immunoassay (DELFIA) for the simultaneous detection and quantitation of diphtheria (D) and tetanus (T) antibodies in sera has been developed. In the double antigen format one arm of the antibody binds to antigen coated microtitre wells and the other arm binds to labelled antigen to provide a fluorescent signal. This assay was found to be functionally specific for IgG antibodies and showed a good correlation with established toxin neutralization assays. Furthermore, the double antigen set-up was species independent, permitting the direct use of existing international references of animal origin to measure protective antibody levels in humans in international units (IU/ml). The detection limit corresponded to 0.0003 IU/ml with Eu(3+)-labelled toxoids and to 0.0035 IU/ml using Sm(3+)-labelled toxoids. The assay was fast with a high capacity making it a suitable method for serological surveillance studies.
authors.affiliation: Statens Seruminstitut, Bacterial Vaccine Department, Copenhagen, Denmark.
authors.forename: H
authors.initials: H
authors.lastname: Aggerbeck
authors.forename: B
authors.initials: B
authors.lastname: Nørgaard-Pedersen
authors.forename: I
authors.initials: I
authors.lastname: Heron
mesh_terms: D000907:Antibodies, Bacterial / Q000032:analysis* / Q000097:blood; D003017:Clostridium tetani / Q000276:immunology*; D003353:Corynebacterium diphtheriae / Q000276:immunology*; D004168:Diphtheria Toxoid / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005069:Evaluation Studies as Topic; D015200:Fluoroimmunoassay / Q000379:methods* / Q000592:standards / Q000706:statistics & numerical data; D006801:Humans; D007074:Immunoglobulin G / Q000032:analysis / Q000097:blood; D007132:Immunoglobulin Isotypes / Q000032:analysis / Q000097:blood; D009500:Neutralization Tests; D012015:Reference Standards; D012680:Sensitivity and Specificity; D013745:Tetanus Toxoid / Q000276:immunology
chemical_list: D000907:Antibodies, Bacterial; D004168:Diphtheria Toxoid; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D013745:Tetanus Toxoid