A Simple Method for the Isolation of the Subcomponents of the First Component of Complement by Affinity Chromatography

Abstract

Abstract The three subcomponents of the first component of human complement, C1q, C1r and C1s have been separated and purified by a simple method with affinity chromatography on a column of chemically modified agarose to which human IgG has been covalently linked. This method employs human serum as a starting material, and separates active C1 from serum without the need for euglobulin precipitation. Large quantities of hemolytically active and physicochemically and immunochemically homogeneous C1s can be obtained by a subsequent preparative polyacrylamide electrophoresis step. C1q and C1r may be purified by DEAE-cellulose chromatography followed by gel filtration on Sephadex G-200. A fourth protein which was recovered from the affinity column appears to be a subcomponent of the C1 complex.