Glycolipids noncovalently bound to DEAE-Sephadex. Use of the complexes for purification of IgM and IgG anti-(Gal beta 1-->3 GalNAc-) antibodies.

A method for the purification by affinity of antibodies of the IgM and IgG classes against the (Gal beta 1-->3 GalNAc-) epitope has been developed. The immunoadsorbent is based on the property of DEAE-Sephadex to bind acid glycolipids bearing this epitope, by electrostatic and hydrophobic interactions in a stable form in an aqueous medium. The acid glycolipid employed was asialo-GM1 ganglioside (GA1) derivatized to produce a carboxyl function on the olefinic bond of the sphingosine moiety (GA1 acid). The DEAE-Sephadex-GA1 acid complex was used to purify the antibodies of the IgG class from serum of an immunized rabbit and of the IgM class from a human serum. The specific activities of the purified antibodies were 1,200- to 2,400-fold higher, and the antibody activities were quantitatively recovered respect to the untreated sera, in both cases. The sequential use of two immunoadsorbents: DEAE-Sephadex-ganglioside and DEAE-Sephadex-GA1 acid, allows the separation of the two classes of immunoglobulins that recognize the same sugar residues in glycolipids.