Physical and biochemical characterization of five commercial resins for immunoaffinity purification of factor IX.

The American Red Cross has developed an immunoaffinity chromatography method to purify human coagulation factor IX (FIX) to homogeneity using monoclonal antibodies (MAb) that bind FIX in the presence of divalent cations. The MAb is immobilized on Sepharose CL2B, a soft gel with a low pressure tolerance as well as poor large-scale performance characteristics, including low reusability, and resin crumbling and deterioration. In this study, we examined several commercially available resin supports. Aside from Sepharose CL2B, we studied two other cross-linked agaroses, as well as two synthetic polymer supports. Immobilization chemistries included cyanogen bromide activation of agarose, 2-fluoro-2 methylpyridinium toluene-4-sulfonate activation of one of the synthetic polymer as well as aldehyde group reduction by NaCNBH3 to form secondary amine linkages on one of the cross-linked agaroses. To determine the feasibility of using the resins in large-scale immunoaffinity chromatographic purification of FIX, we studied physical and biochemical properties of the resins. The physical characteristics studied included the crushability of the resins under pressure as well as ability to support increasing flow-rates at increasing pressures. The biochemical examination of the various resins focused on efficiency of antigen capture by the immobilized antibody ligand and the effect of flow-rate on MAb efficiency, where we found that very low flow-rates slightly increased the capacity of the MAb. The results demonstrate a straightforward method of assessing the feasibility of using particular resins in large-scale affinity purification.