Purification of a bivalently active antibody using a non-chromatographic method

A method of purifying bivalent antibodies or antibody fragments that are active at both Fab sites from a source of antibodies or antibody fragments using a non-chromatographic method comprising:

• (a) inducing the formation of cyclic immunoglobulin aggregates by addition of multivalent hapten to a salt solution of soluble antibodies or antibody fragments, wherein said multivalent hapten possesses a linker between the multiple haptens effective to prevent the binding of the multiple haptens to the same antibody or antibody fragment, and wherein the salt in the salt solution is present at a concentration sufficient to precipitate cyclic immunoglobulin aggregates;
• (b) recovering the cyclic immunoglobulin aggregates from the salt solution;
• (c) dissolving the cyclic immunoglobulin aggregates recovered in (b) and dissociating the cyclic immunoglobulin aggregates from the multivalent haptens by addition of excess monovalent hapten;
• and
• (d) separating the antibodies or antibody fragments from the monovalent and multivalent haptens.