Biochemical studies of immune complexes. I. Isolation of circulating immune complexes using a bifunctional exclusion...

A simple and rapid method of isolating immune complexes from serum is described. The method utilizes the binding properties of a bifunctional chromatography matrix consisting of diethylaminoethyl and Cibacron blue F3GA functional groups linked to agarose beads. This column matrix binds all normal serum proteins except IgG and transferrin, excluding these proteins, and permitting them to be collected in the wash-through, void volume. Immune complexes prepared in vitro with human serum albumin were rapidly isolated from starting serum by this method. This method may have general application for the purification of immune complexes from serum in pathological conditions and should foster subsequent biochemical and immunological studies, including identification and characterization of immune complex antigens.