title: Recombinant protein to analyze autoantibodies to proteinase 3 in systemic vasculitis.
abstract: The presence of antineutrophil cytoplasmic autoantibodies with specificity for proteinase 3 (PR3-ANCA) usually is detected by enzyme-linked immunosorbent assay (ELISA) with purified PR3 as a substrate. We studied the technical performance of direct and capture ELISA using a recombinant proteolytically inactive form of PR3 produced in the baculovirus expression system for the detection of PR3-ANCA in 114 patients with systemic vasculitis at diagnosis. We found that ELISA using recombinant PR3 produced in insect cells is a promising alternative for ELISA with native PR3. We found a correlation between tests using recombinant or native PR3, as well as correlation of the ELISA results with ANCA titers measured by the indirect immunofluorescence technique. However, the specificity for ANCA-associated vasculitis of ELISA with recombinant PR3 was lower than ELISA using native PR3. Compared with the direct assay, capture ELISA is a more sensitive method for PR3-ANCA detection, with both native and recombinant PR3, and its results depend on the monoclonal antibody used to capture the antigen.
authors.affiliation: Department of Internal Medicine, University Hospital Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands.
authors.forename: Agnieszka A
authors.initials: AA
authors.lastname: Rarok
authors.forename: Minke G
authors.initials: MG
authors.lastname: Huitema
authors.forename: Marcel J
authors.initials: MJ
authors.lastname: van der Leij
authors.forename: Ymke M
authors.initials: YM
authors.lastname: van der Geld
authors.forename: Heike
authors.initials: H
authors.lastname: Berthold
authors.forename: Jacky
authors.initials: J
authors.lastname: Schmitt
authors.forename: Coen A
authors.initials: CA
authors.lastname: Stegeman
authors.forename: Pieter C
authors.initials: PC
authors.lastname: Limburg
authors.forename: Cees G
authors.initials: CG
authors.lastname: Kallenberg
mesh_terms: D000818:Animals; D019268:Antibodies, Antineutrophil Cytoplasmic / Q000276:immunology*; D000911:Antibodies, Monoclonal; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005260:Female; D019084:Fluorescent Antibody Technique, Indirect; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D053146:Myeloblastin; D011994:Recombinant Proteins / Q000276:immunology* / Q000378:metabolism; D012680:Sensitivity and Specificity; D012697:Serine Endopeptidases / Q000276:immunology* / Q000378:metabolism; D018411:Spodoptera / Q000235:genetics / Q000378:metabolism; D014657:Vasculitis / Q000175:diagnosis / Q000201:enzymology / Q000276:immunology*; D014764:Viral Proteins / Q000276:immunology / Q000378:metabolism
chemical_list: D019268:Antibodies, Antineutrophil Cytoplasmic; D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D014764:Viral Proteins; D012697:Serine Endopeptidases; D053146:Myeloblastin