Development and characterization of an automated high throughput screening method for optimization of protein refolding processes

Refolding and purification of cGMP-grade recombinant human neurturin from Escherichia coli inclusion bodies

Neurturin is a potent neurotrophic factor that has been investigated as a potential therapeutic agent for the treatment of neurodegenerative diseases, including Parkinson's disease, and, more recently, for the treatment of type II diabetes. However, purification of neurturin for clinical applications has been hampered by its low solubility in aqueous solutions. Here we describe the development of a scalable manufacturing process for recombinant neurturin from E. coli. inclusion bodies. Neurturin was refolded from solubilized inclusion bodies by fed-batch dilution refolding with a titer of 90 mg per liter refold and a refold yield of 89%. A two-step purification process using cation exchange and hydrophobic interaction chromatography, followed by formulation using tangential flow filtration resulted in an overall process yield of about 56 mg purified neurturin per liter refold. Solubility of neurturin during the purification process was maintained by the addition of 15% (w/v) glycerol to all buffers. For clinical applications and parenteral administration glycerol was replaced by 15% (w/v) sulfobutyl ether-beta-cyclodextrin (i.e. Captisol) in the drug substance formulation buffer. The final purified product had low or undetectable levels of product-related impurities and concentrations of process-related contaminants such as host cell proteins, host cell DNA, endotoxins and Triton X-100 were reduced more than 10,000-fold or below the limit of detection. Bioactivity of purified recombinant neurturin was demonstrated in a cell-based assay by activation of the MAPK signaling pathway.

Bioscreening and expression of a camel anti-CTGF VHH nanobody and its renaturation by a novel dialysis-dilution method

The variable regions of the camel heavy chain antibody, also known as nanobody is the smallest antibody with antigen-binding efficiency. CTGF is considered important during extracellular matrix deposition which was involved in the pathogenesis of fibrosis related diseases. There are several anti-CTGF-C nanobody drugs under developing in pharmacy. In this study, we described the screening of a novel anti-CTGF-C nanobody from the peripheral blood of immunized camel by phage display. The screened nanobody was further expressed and purified from E. coli cells. A sophisticated dialysis–dilution method was designed for the in vitro refolding of the nanobody. The results showed that the expressed nanobody was consisted of 135 amino acid and mainly expressed as inclusion body in E. coli cells. The dialysis–dilution method was very effective and the recovery rate of the renaturation was more than 80 %. The ELISA result suggested the nanobody had been well refolded showing a superior CTGF binding activity to the commercial mouse anti-CTGF-C mAb. In conclusion, the anti-CTGF-C nonobody had been successfully screened by phage display. The dialysis–dilution refolding method was very effective and the recovery rate reached over 80 %.

Downstream process development strategies for effective bioprocesses: Trends, progress, and combinatorial approaches

The biopharmaceutical industry is at a turning point moving toward a more customized and patient-oriented medicine (precision medicine). Straightforward routines such as the antibody platform process are extended to production processes for a new portfolio of molecules. As a consequence, individual and tailored productions require generic approaches for a fast and dedicated purification process development. In this article, different effective strategies in biopharmaceutical purification process development are reviewed that can analogously be used for the new generation of antibodies. Conventional approaches based on heuristics and high-throughput process development are discussed and compared to modern technologies such as multivariate calibration and mechanistic modeling tools. Such approaches constitute a good foundation for fast and effective process development for new products and processes, but their full potential becomes obvious in a correlated combination. Thus, different combinatorial approaches are presented, which might become future directions in the biopharmaceutical industry.