Abstract: A novel non-chromatographic ion-exchange adsorption technique was developed to purify polyclonal antibody against Vibrio parahaemolyticus from rabbit serum using carboxylated superparamagnetic nanobeads. pH and NaCl concentration of adsorption and desorption buffers and Tween-20 concentration in washing buffer were studied, and the developed method was compared with caprylic acid-ammonium sulfate precipitation and SPA affinity chromatography. The results showed that the polyclonal antibody could be completely adsorbed by magnetic beads in 0.01 mol/L phosphate buffer (pH 6.0) and desorbed in 0.01 mol/L phosphate buffer (pH 8.0) containing 0.3 mol/L NaCl, and unadsorbed proteins were removed by washing twice with washing buffer containing 0.1% Tween-20. After the purification, the polyclonal IgG purity was 82.6%, the recovery yield 58.0%, and the titer 1/64000. In total, 10 mL of rabbit serum could be treated by 1 g of magnetic beads, and the whole process could be finished within 1 h. The method has obvious advantages compared with caprylic acid-ammonium sulfate precipitation and SPA affinity chromatography, thereby presenting a promising application prospect.

Key words: magnetic beads, ion-exchange adsorption, antibody purification