title: Production of recombinant PSA and HK2 and analysis of their immunologic cross-reactivity.
abstract: Measurements of prostate-specific antigen (PSA) in serum are widely used to monitor patients with prostate cancer, but the attenuation of the assay response by PSA complexed to protease inhibitors has been shown to affect the results in certain assay designs. Moreover, the human glandular kallikrein-2 (hK2), a kallikrein-like serine protease that is 80% similar to PSA, might interfere with the specific detection of PSA by immunological cross-reactivity. We have expressed hK2 and PSA in eucaryotic cells using the Semliki Forest Virus expression system and studied the reactivity of 18 monoclonal anti-PSA IgGs. Five of them cross-reacted with identical affinities to recombinant hK2 whereas 13 recognized PSA alone. The antibodies that recognized both PSA and hK2 bind to a region of the protein that is exposed when PSA is complexed to alpha-1-antichymotrypsin.
authors.affiliation: Department of Clinical Chemistry, Lund University, University Hospital, Malmö, Sweden.
authors.forename: J
authors.initials: J
authors.lastname: Lövgren
authors.forename: T
authors.initials: T
authors.lastname: Piironen
authors.forename: C
authors.initials: C
authors.lastname: Overmo
authors.forename: B
authors.initials: B
authors.lastname: Dowell
authors.forename: M
authors.initials: M
authors.lastname: Karp
authors.forename: K
authors.initials: K
authors.lastname: Pettersson
authors.forename: H
authors.initials: H
authors.lastname: Lilja
authors.forename: A
authors.initials: A
authors.lastname: Lundwall
mesh_terms: D000911:Antibodies, Monoclonal / Q000276:immunology; D000937:Antigen-Antibody Reactions; D003001:Cloning, Molecular; D003429:Cross Reactions; D006801:Humans; D007610:Kallikreins / Q000235:genetics* / Q000276:immunology; D017430:Prostate-Specific Antigen / Q000235:genetics* / Q000276:immunology; D011994:Recombinant Proteins / Q000235:genetics / Q000276:immunology; D012672:Semliki forest virus / Q000235:genetics; D020840:Tissue Kallikreins
chemical_list: D000911:Antibodies, Monoclonal; D011994:Recombinant Proteins; D007610:Kallikreins; D020840:Tissue Kallikreins; D017430:Prostate-Specific Antigen