Protein A affinity chromatography continues to be the preferred method for commercial purification of antibodies because of its high selectivity and robust resin performance over repeated purification cycles. Reports estimate that US$125 billion of yearly sales will be generated from monoclonal antibody (MAb) products by 2020 (1). Most of those will be purified by largescale protein A affinity chromatography. With the continued growth and commercial importance of MAb production, availability of high-quality resin material and options for secondary sourcing are…