[Effectiveness of methods of isolating specific class-G rabbit antibodies for the immunoenzyme determination of human placental alkaline phosphatase].

Four different chromatographic methods of IgG isolation from rabbit antisera to placental alkaline phosphatase (HPAP) have been compared. The antibodies were obtained by ion-exchange chromatography and affinity chromatography on protein-A-sepharose, on the sepharose with immobilized antigen. IgG samples were characterized by the content of specific antibodies to HPAP and checked in enzyme immunoassay (EIA). IgG purified on immobilized antigen were found to be the optimal both from the point of view of the specific antibodies content and EIA sensitivity, but satisfactory results could be also obtained with ion-exchange and protein-A-chromatography purified IgG. The last two isolation methods are simpler and provide 3-10 ng/ml sensitivity of HPAP detection, which is lower, as compared with the test employing affinity antibodies (1 ng/ml), but allows the detection of HPAP in serum samples.