[Isolation and purification of specific beta1-G-globulin].

Antigen, specific for trophoblastic tumor, was isolated from retroplacental blood by means of ion exchange chromatography on DEAE cellulose, gel filtration on Sephadex G-200, chromatography on hydroxylapatite and CM-cellulose and by preparative isofocusing using ampholines. Distinct heterogeneity of the protein and alteration in several its properties were observed as purity of the preparation was increased in course of isolation. A series of the protein preparations was obtained with 90-95% purity and with similar immunologic properties but the preparations differed in electrophoretic mobility, isoelectric points and some other patterns.