Prostate-specific acid phosphatase: purification and specific antibody production in rabbits

Demonstration of prostate-specific acid phosphatase by immunologic methods in tissue sections or in plasma necessitates a monospecific antiserum. This is produced by immunizing rabbits with pure prostate-specific acid phosphatase antigen, prepared from seminal fluid. The ejaculate is centrifuged, dialyzed against a citrate buffer, pH 4.8, and centrifuged again. The supernatant is brought onto a Sephacryl S-200 Superfine column and eluted with the same buffer. Prostate-specific acid phosphatase-positive fractions are concentrated, brought onto and stepwise eluted from a Sulphopropyl Sephadex column with citrate buffers at pH 4.8, 5.2, and 5.5. Fractions containing prostate-specific acid phosphatase are concentrated again and purified over a Blue Sepharose CL-6 B column. After elution, a new concentration step yields a protein concentration of 0.5-1.0 mg . ml-1. This sample in polyacrylamide gel electrophoresis shows a single protein band and is used to immunize female rabbits. The purity of the antiserum is then tested by immunoelectrophoresis and an Ouchterlony technic. Besides anti-prostate-specific acid phosphatase, two other antibodies against serum proteins are present, one of which is anti-albumin. Absorption of these impurities results in a monospecific antiserum against prostate-specific acid phosphatase.