Why is Protein A chromatography important for antibody purification?

Protein A chromatography is the gold standard for monoclonal antibody purification due to its high specificity for the Fc region of IgG antibodies. It provides >95% purity in a single step with high yields (>90%). The process involves: loading clarified cell culture harvest onto the column where antibodies bind, washing to remove impurities (host cell proteins, DNA, media components), and eluting antibodies at low pH (3.0-3.5). Advantages include platform applicability across different antibodies and robust performance. Challenges include high resin cost, ligand leaching, and required low pH elution. Protein A remains the primary capture step in virtually all antibody manufacturing processes.