Characterization of 10 new monoclonal antibodies against prostate-specific antigen by analysis of affinity, specificity and function in sandwich assays.
While prostate-specific antigen (PSA) is already an invaluable marker for prostate cancer, there is continuing demand for new anti-PSA antibodies with specific characteristics, e.g., high sensitivity and specificity and equimolar binding to free PSA (f-PSA) and the PSA-alpha-1-antichymotrypsin complex (PSA-ACT), as well as the ability to distinguish between these 2 immunoreactive forms of PSA. We have therefore generated and characterized 10 anti-PSA monoclonal antibodies (MAbs). Apparent dissociation constants (Kd) of MAbs were determined by direct ELISA yielding Kd-0.2-164.0 nM. Western blots suggested that 3 of the MAbs (60-1A2, 60-8A2 and 17-1A2) bind to linear epitopes. Sandwich assays identified 5 major antigenic regions as binding targets of the MAbs. Three combinations of MAbs recognize f-PSA and PSA-ACT in equimolar fashion with high sensitivity. Two of the MAb combinations are specific for f-PSA. Physical analysis of the new antibodies has allowed us to assign the MAbs to binding classes (based on their sandwiching capabilities) and to determine accurate apparent dissociation constants.
Corey
E
E
Urology Department, The School of Medicine of the University of Washington, Seattle 98195, USA.
Wegner
S K
SK
Stray
J E
JE
Corey
M J
MJ
Arfman
E W
EW
Lange
P H
PH
Vessella
R L
RL
D000818:Animals; D000911:Antibodies, Monoclonal / Q000276:immunology*; D000915:Antibody Affinity; D000918:Antibody Specificity; D015153:Blotting, Western; D004797:Enzyme-Linked Immunosorbent Assay; D051379:Mice; D008807:Mice, Inbred BALB C; D017430:Prostate-Specific Antigen / Q000276:immunology*; D012680:Sensitivity and Specificity
D000911:Antibodies, Monoclonal; D017430:Prostate-Specific Antigen