Immunofluorometric assay for sensitive and specific measurement of human prostatic glandular kallikrein (hK2) in serum
Prostate-specific antigen (PSA) and human prostatic glandular kallikrein (hK2) have 79% identity with the primary structure. When we used recombinant hK2 protein, only 7 of 23 monoclonal anti-PSA IgGs (monoclonal antibodies, MAbs) cross-reacted with hK2, which enabled us to design a novel immunofluo...
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Published in | Clinical chemistry (Baltimore, Md.) Vol. 42; no. 7; pp. 1034 - 1041 |
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Main Authors | , , , , , , , , |
Format | Journal Article |
Language | English |
Published |
Washington, DC
Am Assoc Clin Chem
01.07.1996
American Association for Clinical Chemistry |
Subjects | |
Online Access | Get full text |
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Summary: | Prostate-specific antigen (PSA) and human prostatic glandular kallikrein (hK2) have 79% identity with the primary structure. When we used recombinant hK2 protein, only 7 of 23 monoclonal anti-PSA IgGs (monoclonal antibodies, MAbs) cross-reacted with hK2, which enabled us to design a novel immunofluorometric MAb-MAb assay for the specific detection of hK2. In the first incubation, an excess of MAb 2H11, which does not cross-react with hK2, is added to prevent both free and complexed PSA from reacting in subsequent immunoreactions. In the second incubation, biotinylated MAb H50, which cross-reacts with hK2 by an epitope overlapping with MAb 2H11, served to bind only hK2 to the microtitration wells coated with streptavidin. In the third step, Eu-labeled MAb H117, which cross-reacts with hK2, detected the immobilized hK2. The hK2 assay was calibrated with recombinant hK2. The detection limit of the assay was 0.1 microgram/L, and the cross-reactivity with recombinant PSA was < or = 0.7%. The concentration of hK2 was measured in serum samples from 334 males with total PSA concentrations ranging from 1 to 3400 microgram/L. Most of the samples (57%) had hK2 concentrations below the detection limit. The proportions of hK2 relative to total PSA were 0-2% in 79%, 2-5% in 14%, 5-10% in 4%, and >10% in 3% of the samples. Gel filtration of 10 serum samples with increased hK2 concentrations showed a single peak of hK2 immunoreactivity with an apparent molecular size of approximately 30 kDa, corresponding to that of recombinant hK2 and free PSA. |
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Bibliography: | ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23 |
ISSN: | 0009-9147 1530-8561 |
DOI: | 10.1093/clinchem/42.7.1034 |