title: Quantitative immunoassay for complexes of prostate-specific antigen with alpha2-macroglobulin.
abstract: We have developed two ELISAs for quantifying complexes of prostate-specific antigen (PSA) with alpha2-macroglobulin (alpha2M), using partially purified PSA:alpha2M complex as the calibrator. One ELISA was designed to evaluate )SA:alpha2M complex in fluids containing a huge excess of PSA over the amount of complex (semen-derived fluids), the other for use in fluids containing an excess of alpha2M over PSA (blood plasma). The range of the assays was 2-1000 micrograms/L for PSA complexed to alpha2M; the detection limit was 3 micrograms/: Intra- and interassay CVs were 7-13% and 11-17%, respectively, at complexed PSA concentrations of 6-500 micrograms/L. Seminal fluid from healthy men (n = 60) contained 5.2 +/- 2.6 micrograms/L PSA complexed with alpha2M. Prostatic and seminal vesicle fluids contained 6.5 +/- 2.9 ad 0.3 +/- 0.2 mg/L PSA complexed to alpha2M, respectively. When purified PSA was incubated with citrated plasma, between 45% and 65% of the added PSA was recovered as free PSA, whereas approximately 25% formed complexes with alpha2M, 10% complexed with alpha1-antichymotrypsin, and only 0.1-6% was complexed with protein C inhibitor. Of 30 patients with prostate disease, 20 showed detectable plasma PSA:alpha2M complexes; however, the potential diagnostic significance of this complex requires further investigation.
authors.affiliation: Research Center, La Fe Univesity Hospital, Valencia, Spain.
authors.forename: F
authors.initials: F
authors.lastname: España
authors.forename: J
authors.initials: J
authors.lastname: Sánchez-Cuenca
authors.forename: A
authors.initials: A
authors.lastname: Estellés
authors.forename: J
authors.initials: J
authors.lastname: Gilabert
authors.forename: J H
authors.initials: JH
authors.lastname: Griffin
authors.forename: M J
authors.initials: MJ
authors.lastname: Heeb
mesh_terms: D000328:Adult; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D008875:Middle Aged; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000097:blood / Q000378:metabolism; D012016:Reference Values; D012661:Semen / Q000737:chemistry*; D000511:alpha-Macroglobulins / Q000032:analysis* / Q000378:metabolism
chemical_list: D000511:alpha-Macroglobulins; D017430:Prostate-Specific Antigen