Purification and characterization of rabbit polyclonal immunoglobulin G using DEAE ion-exchange chromatography and dynamic light scattering.

Weak anion-exchange chromatography (AEC) provides a mild alternative to ammonium sulfate (AS) precipitation for antibody purification, but its mechanistic behavior in complex serum systems remains unclear. This study evaluates pH-dependent DEAE flow-through purification of rabbit anti-HBcAg IgG and compares it with AS precipitation. At pH 8.0, DEAE chromatography achieved 94% recovery and 83% purity, consistent with reduced IgG-resin interaction and selective retention of anionic serum proteins. Conductivity profiling showed a 69% reduction in ionic strength relative to AS-treated samples, correlating with improved structural homogeneity. Dynamic light scattering revealed a monomodal ∼10 nm hydrodynamic diameter for DEAE-purified IgG, whereas AS precipitation generated multimodal distributions indicative of aggregation. These results clarify how pH, ionic strength, and protein-protein interactions govern IgG behavior during weak AEC. The findings position DEAE chromatography as a gentle, aggregation-minimizing, and scalable method for producing high-quality polyclonal antibodies for diagnostic applications.