Conjugated surfactant micelles: A non‐denaturing purification platform for concentrated human immunoglobulin G

• Published in: Nano select 2023-06, Vol.4 (6), p.386-394
• Main Authors: Dhandapani, Gunasekaran, Wachtel, Ellen, Patchornik, Guy
• Format: Article
• Language: English
• Subjects: Aggregates; Antibodies; Bacterial proteins; Batch processes; Cell culture; Chromatography; Detergents; downstream processing; E coli; IgG antibody; Immunoglobulins; Ligands; micellar conjugation; Micelles; Monoclonal antibodies; Photon correlation spectroscopy; Protein A chromatography; Purification; Reagents; Sodium; Surfactants; Tyrosine
• ISSN: 2688-4011; 2688-4011
• DOI: 10.1002/nano.202200251

As downstream purification and separation technologies progress towards raising the concentration of therapeutic‐grade monoclonal antibodies (mAbs) in cell culture, downstream processing has begun to face increased difficulty in efficiently coping with such high immunoglobulin G (IgG) titers (≤25 mg mL−1). In the current study, we demonstrate the ability of a non‐chromatographic, ligand‐free procedure to recover almost quantitatively (84–99% yield, by densitometry) polyclonal, human IgG present at high concentrations (15–25 mg mL−1) in E. coli lysate. Instead of chromatographic media and columns, we use conjugated, mixed‐micelles comprising non‐ionic detergents, tyrosine monomers, and the amphiphilic [(bathophenanthroline)3:Fe2+] complex. Capture and extraction processes are performed at pH 6.5–7, thereby avoiding antibody exposure to acidic, potentially denaturing conditions. Recovered IgG is monomeric as determined by dynamic light scattering (DLS). Process upscaling from 0.1 to 5 mL requires only proportional increase in all reagents and does not affect overall yield or antibody purity. Non‐ionic detergent mixed‐micelles, conjugated via [metal:chelator] complexes, and with added Tyr monomers, allow efficient capture and recovery of pure antibodies (IgG's) at high concentration near neutral pH, in the presence of E. Coli lysate as an artificial contamination background. This non‐chromatographic strategy aims at providing an economical platform for efficient purification of IgG's at expression levels expected to reach ≥25 mg mL−1.