title: Prostate-specific antigen: characterization of epitopes by synthetic peptide mapping and inhibition studies.
abstract: To improve our understanding of the prostate-specific antigen (PSA) antigenic regions, we studied the association targets of one anti-PSA polyclonal antibody and 10 anti-PSA monoclonal antibodies (mAbs). We also examined the ability of the mAbs to inhibit PSA enzymatic activity and block the association of PSA with alpha 1-antichymotrypsin (ACT). Linear epitope mapping with a polyclonal antibody indicated the presence of six major antigenic regions in PSA. Examination of the panel of mAbs established that three of them bind to linear epitopes. Five of the mAbs inhibited > 90% of PSA enzymatic activity. However, inhibition of PSA enzymatic activity and hindrance of PSA-ACT association by mAbs cannot be used to predict whether the mAbs bind to free PSA, the PSA-ACT complex, or both. Some of the mAbs may block PSA-ACT association through peripheral occlusion of the binding site, or through induction of conformational changes in PSA.
authors.affiliation: Tumor Immunology Laboratory, School of Medicine of the University of Washington, Seattle 98195, USA. ecorey@u.washington.edu
authors.forename: E
authors.initials: E
authors.lastname: Corey
authors.forename: S K
authors.initials: SK
authors.lastname: Wegner
authors.forename: M J
authors.initials: MJ
authors.lastname: Corey
authors.forename: R L
authors.initials: RL
authors.lastname: Vessella
mesh_terms: D000595:Amino Acid Sequence; D000911:Antibodies, Monoclonal / Q000378:metabolism / Q000494:pharmacology; D018604:Epitope Mapping; D000939:Epitopes / Q000737:chemistry* / Q000276:immunology; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D017430:Prostate-Specific Antigen / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000276:immunology*; D000514:alpha 1-Antichymotrypsin / Q000378:metabolism
chemical_list: D000911:Antibodies, Monoclonal; D000939:Epitopes; D000514:alpha 1-Antichymotrypsin; D017430:Prostate-Specific Antigen