An artificial protein L for the purification of immunoglobulins and Fab fragments by affinity chromatography

The development and characterization of an artificial protein L (PpL for the affinity purification of antibodies is described. Ligand 8/7, which emerged as the lead from a de novo designed combinatorial library of ligands, inhibits the interaction of PpL with IgG and Fab by competitive ELISA and shows negligible binding to Fc. The ligand 8/7 adsorbent (K-a similar to 10(4) M-1) compared well with PpL in binding to immunoglobulins from different classes and sources and, in addition, bound to IgG(1), with kappa and gimel isotypes (92% and 100% of loaded protein) and polyclonal IgG from sheep, cow, goat and chicken. These properties were also reflected in the efficient isolation of immunoglobulins from crude samples. (C) 2004 Elsevier B.V. All rights reserved.