Abstract
Human IgG separated by Cohn fractionation showed variability in the content of aggregates, plasminogen and anticomplement activity. The plasminogen was removed or markedly reduced by affinity chromatography on Sepharose-lysine. Anticomplement activity was reduced by chromatography of Cohn fraction II on DEAE-cellulose. Preparations of IgG obtained by chromatography of intermediates from Cohn fractionation (e.g. Cohn FII + FIII or FII + FIII W) on DEAE-cellulose were devoid of aggregates, plasminogen and exhibited reduced anticomplement activity. The initial levels of specific antibody activity to viral agents were recovered in the IgG fractions. Fragmentation of IgG during storage was prevented or greatly reduced by removal of plasminogen by affinity chromatography on Sepharose-lysine.