High cytoplasmic expression in E. coli, purification, and in vitro refolding of a single chain Fv antibody fragment against the hepatitis B surface antigen

• Published in: Journal of biotechnology 1999-06, Vol.72 (1), p.13-20
• Main Authors: Sánchez, Leticia, Ayala, Marta, Freyre, Freya, Pedroso, Idolka, Bell, Hansell, Falcón, Viviana, Gavilondo, Jorge V.
• Format: Article
• Language: English
• Subjects: Affinity chromatography; Amino Acid Sequence; Amino acids; Animal cell culture; Antibodies; Antigens; Base Sequence; Bioassay; Biological and medical sciences; Biotechnology; Cloning, Molecular; Density (optical); DNA Primers; Electrophoresis, Polyacrylamide Gel; Enzyme-Linked Immunosorbent Assay; Escherichia coli; Escherichia coli - genetics; Extraction; Fundamental and applied biological sciences. Psychology; Health. Pharmaceutical industry; Hepatitis B surface antigen; Hepatitis B Surface Antigens - immunology; Humans; Immunoglobulin Variable Region - genetics; Immunoglobulin Variable Region - immunology; Immunoglobulin Variable Region - isolation & purification; Industrial applications and implications. Economical aspects; Microscopy, Electron; Molecular Sequence Data; Monoclonal antibodies; Production of active biomolecules; Protein Folding; Recombinant antibody fragments; Recombinant Proteins - genetics; Recombinant Proteins - immunology; Recombinant Proteins - isolation & purification; Single chain Fv antibody fragment; Solubility
• ISSN: 0168-1656; 1873-4863
• DOI: 10.1016/S0168-1656(99)00036-X

A single-chain Fv (scFv) antibody fragment against the hepatitis B surface antigen (HBsAg) was expressed in Escherichia coli in the form of two independent fusion proteins, with either 60 (‘long’) or 27 (‘short’) amino acid N-terminal encoding sequences related to human interleukin-2. Both fusion proteins were expressed insolubly and at high levels in the bacterial cytoplasm (approximately 30% of total bacterial protein in MM294 cells at a laboratory scale). When recombinant cells were cultured in 5-l fermentors, expression and optical density increased 2- and 4-fold, respectively, compared to a previous periplasmic insoluble version of the same anti HBsAg scFv. After extraction and solubilization in urea, the cytoplasmic scFvs were purified using immobilized metal ion affinity chromatography, followed by DTT treatment, and refolding by dialysis against a basic pH buffer containing EDTA. The refolded scFvs recognized the recombinant HBsAg in ELISA. Results of an ELISA where antigen affinity chromatography repurified scFvs were used as standards, indicated that refolding efficiencies were high: 56.2% for the ‘short’ fusion scFv, and 50.6% for the ‘long’ fusion scFv. Corrected final yields of active scFv were 30.3 and 27.3 mg l −1, respectively, for the aforementioned fusion proteins, 5–6 times better than those reported for the periplasmic scFv variant.