Removal of anticomplementary activity from human immune serum globulins by treatment with purified human plasmin

Human immune serum globulin preparations were treated with highly purified human plasmin to remove their anticomplementary activity. The extent of anticomplementary activity removed and the amount of fragmentation obtained from immune serum globulin preparation depended upon the amount of plasmin added and the length of incubation time. The enzymatic reaction was stopped by removing plasmin with bentonite adsorption. Two types of plasmin-treated immune serum globulin that may be used for intravenous injection were obtained. One was a more fragmented product (35 to 45%) with lower anticomplementary activity, the other was a less degraded product (15 to 20%) with slightly higher anticomplementary activity. Antibody content of the former preparation was somewhat reduced while that of the latter preparation was virtually unchanged from the untreated immune serum globulin.