A simplified method for the preparation of immune-serum globulin

This report describes the recovery of highly purified immune-serum globulin (ISG) from the 42% ethanol precipitate fraction (42% P) generated during the first step of albumin purification. The method consists of three purification steps: (1) reprecipitation of the 42% P at 20% ethanol, pH 7.2; (2) solubilization of ISG at 17% ethanol, pH 5.2, and (3) isoelectric precipitation of ISG at 25% ethanol, pH 7.2. ISG prepared by this method was homogeneous when subjected to immunoelectrophoresis and polyacrylamide gel electrophoresis, and gave a yield equivalent to 4.7 g/l plasma, corresponding to a final recovery of over 48%.