Antigenic determinants of prostate-specific antigen (PSA) and development of assays specific for different forms of PSA.
Monoclonal antibodies were raised against prostate-specific antigen (PSA) by immunization with purified free PSA, i.e. not in complex with any protease inhibitor (F-PSA) and PSA in complex with alpha1-anti-chymotrypsin (PSA-ACT). Epitope mapping of PSA using the established monoclonal antibody revealed a complex pattern of independent and partly overlapping antigenic domains in the PSA molecule. Four independent antigenic domains and at least three partly overlapping domains were exposed both in F-PSA and in the PSA-ACT complex, while one antigenic domain was specific for F-PSA. The different domains contained both continuous and discontinuous epitopes. The combination of antibodies recognizing antigenic domains exposed both in F-PSA and PSA-ACT made it possible to develop several highly sensitive sandwich immunoassays for determination of total PSA, i.e. F-PSA + PSA-ACT, with the same molar response for F-PSA and PSA-ACT. Assays specific for F-PSA (cross-reactivity between F-PSA and PSA-ACT < 1%) were developed by the combination of antibodies recognizing epitopes exposed only in F-PSA and antibodies recognizing epitopes exposed both in F-PSA and PSA-ACT.
Nilsson
O
O
CanAg Diagnostics AB, Gothenburg, Sweden.
Peter
A
A
Andersson
I
I
Nilsson
K
K
Grundström
B
B
Karlsson
B
B
D000818:Animals; D000911:Antibodies, Monoclonal / Q000145:classification / Q000276:immunology; D015153:Blotting, Western; D003429:Cross Reactions; D004306:Dose-Response Relationship, Immunologic; D000939:Epitopes / Q000032:analysis*; D005260:Female; D006801:Humans; D007124:Immunoenzyme Techniques; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D017430:Prostate-Specific Antigen / Q000032:analysis / Q000037:antagonists & inhibitors / Q000276:immunology*; D000511:alpha-Macroglobulins / Q000032:analysis / Q000276:immunology*
D000911:Antibodies, Monoclonal; D000939:Epitopes; D000511:alpha-Macroglobulins; D017430:Prostate-Specific Antigen