Separation of Immune Interferon and MIF

A preparation of mitogen-induced immune interferon and MIF was subjected to sequential salt precipitation with first 55% and then 80% saturated ammonium sulfate. At least 95% of the interferon activity was found in the reconstituted 55-80% precipitate, while MIF activity was found in both precipitates, but most active in the reconstituted 55% salt precipitate. The immune interferon and MIF activities of the 55-80% reconstituted salt precipitate were shown to be different by BSA-Affi-Gel 10 affinity chromatography. Both lymphokines were also shown to be heterogeneous by the above techniques.