Separation of human Fab fragments by negative chromatography on ω-aminohexyl- and poly(ethyleneimine)-agarose

Abstract

Polyamines ω-aminohexyl and poly(ethyleneimine) (PEI) immobilized on agarose gel were evaluated as ligands for the purification of Fab fragments from papain-digested human immunoglobulin G (IgG) solution by negative chromatography. The adsorption of proteolytic fragments was investigated using different buffer systems and pH values. The results showed that the buffer system and pH had stronger effects on the adsorption of the proteolytic fragments onto ω-aminohexyl-agarose than onto PEI-agarose. Tris-HCl buffer pH 8.0 could be used to purify Fab fragments by negative chromatography using both adsorbents, achieving purity and recovery above 96% and 93%, respectively. Static binding experiments were conducted to determine the maximum binding capacity of ω-aminohexyl-agarose adsorbent (Qm). The experimental isotherm was best described by the Langmuir–Freundlich model, which indicated the positive cooperativity of adsorption (n = 1.68) and a Qm value of 44.32 mg mL−1 of gel. The results suggest that negative chromatography on ω-aminohexyl- and PEI-agarose is a potential technique for the purification of Fab fragments from papain-digested human IgG solution.