A preliminary study for isolation of catalytic antibodies by histidine ligand affinity chromatography as an alternative to conventional protein A/G methods

Catalytic autoimmune antibodies from the sera of lupus patients were purifi ed using histidyl-aminohexyl-Sepharose gel and compared with the antibodies purified with protein A and protein G affinity chromatography. The IgG pre parations from the histidine affinity column had a much higher catalytic ac tivity in hydrolyzing the peptide substrate Pro-Phe-Arg-methyl-coumarinamid e compared to the antibodies obtained by the conventional protein A/G metho d. This preservation of catalytic activity is attributed to the gentle buff er conditions used in the histidine ligand method that allowed the integrit y of three-dimensional structure of purified catalytic antibodies. Thus, hi stidine affinity offer a superior method for isolating autoimmune catalytic antibodies.