Two-site monoclonal antibody-based immunoradiometric assay for measuring prostate secretory protein in serum

• Published in: Clinical chemistry (Baltimore, Md.) Vol. 38; no. 6; pp. 817 - 823
• Main Authors: Huang, CL, Liang, HM, Brassil, D, Schellhammer, PF, Rozzell, M, Newhall, K, Beckett, ML, Wright, GL, Jr
• Format: Journal Article
• Language: English
• Published: Washington, DC Am Assoc Clin Chem 01.06.1992; American Association for Clinical Chemistry
• Subjects: Antibodies, Monoclonal; Biological and medical sciences; Carrier Proteins - blood; Female; Freezing; Host-tumor relations. Immunology. Biological markers; Humans; Immunoradiometric Assay - standards; Immunoradiometric Assay - statistics & numerical data; Male; Medical sciences; Menopause; Middle Aged; Pregnancy; Prostatic Hyperplasia - blood; Prostatic Neoplasms - blood; Prostatic Secretory Proteins; Quality Control; Reference Values; Tumors; Assay; Tumor; Tumoral marker; Monoclonal antibody; Prostatic disease; Immunological method
• ISSN: 0009-9147; 1530-8561
• DOI: 10.1093/clinchem/38.6.817

We developed a double-determinant immunoradiometric assay for measuring serum prostate secretory protein (PSP), using monoclonal antibodies (MAb) against two different epitopes: MAb PSP-19 was the capture antibody and MAb PSP-6 was the tracer antibody. Assay sensitivity was 0.1 microgram/L. Analytical recovery of PSP was 93.5-104.6%, whereas the intra- and interassay mean CVs were 4.2% and 6.9%, respectively. In 92 normal men, ages greater than 50 years, the mean PSP concentration was 5.7 micrograms/L, with 10 (10.9%) men having concentrations greater than 10 micrograms/L. In contrast, 20 of 49 (40.8%) patients with benign prostate hyperplasia (BPH; mean PSP concentration 9.4 micrograms/L) and 46 of 100 (46%) patients with prostate cancer (mean PSP concentration 22.2 micrograms/L) had PSP concentrations greater than 10 micrograms/L. Mean serum PSP concentrations of the BPH (P less than 0.05) and prostate cancer (P less than 0.01) groups were significantly different from those of age-matched normal men. In a small group of patients, serial PSP concentrations correlated with the clinical course during therapy. Thus, PSP may be a useful marker for evaluating patients with prostate cancer.