Three immunoassays based on monoclonal antibodies specific for prostate specific antigen (PSA), alpha-1-antichymotrypsin (ACT), and the PSA-ACT complex.
BACKGROUND
Prostate specific antigen (PSA) has been widely used as a biomarker for the screening and diagnosis of prostate cancer. PSA in serum predominantly exists as a complex with alpha-1-antichymotrypsin (ACT), and measurement of free PSA and the PSA-ACT complex may improve the utility of the serum PSA assay for differential diagnosis of prostate cancer and non-malignant prostate diseases, such as benign prostatic hyperplasia (BPH).


METHODS
Monoclonal antibodies (MAbs) against PSA, ACT, and the PSA-ACT complex were produced by immunizing mice with an incubated mixture of PSA and ACT, and characterized by Western blot analyses and several enzyme-linked immunosorbant assay (ELISA) methods.


RESULTS
The MAbs produced in this study are capable of distinguishing the PSA-ACT complex from free PSA and ACT. Four MAbs have been selected and utilized to construct three ELISA systems for the separate measurements of free PSA, the PSA-ACT complex, and total PSA.


CONCLUSIONS
The three PSA assay systems developed in this study can specifically measure free PSA, total PSA, and the PSA-ACT complex with equal molar sensitivity. It is expected that these PSA assay systems could be useful in the diagnosis of prostate cancer.
Wan
X Steven
XS
Department of Radiation Oncology, University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104--6072, USA. xswan@mail.med.upenn.edu
Xu
Y Anne
YA
Ware
Jeffrey H
JH
Kennedy
Ann R
AR
D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology*; D000918:Antibody Specificity; D015153:Blotting, Western; D003937:Diagnosis, Differential; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D006801:Humans; D006825:Hybridomas; D008297:Male; D051379:Mice; D017430:Prostate-Specific Antigen / Q000032:analysis* / Q000276:immunology*; D011470:Prostatic Hyperplasia / Q000175:diagnosis; D011471:Prostatic Neoplasms / Q000175:diagnosis; D012680:Sensitivity and Specificity; D000514:alpha 1-Antichymotrypsin / Q000032:analysis* / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000514:alpha 1-Antichymotrypsin; D017430:Prostate-Specific Antigen