In addition to variation due to manufacturing processes, differences between products were observed

In addition to variation due to manufacturing processes, differences between products were observed.5Because cell cultures, cell lines, and the products themselves can vary in cell cultures expressing two different antibody products, the underlying causes for these reduction differences could not be determined. process parameters contribute to the extent of antibody reduction during production. Keywords:antibody disulfide reduction, free cysteine, harvest, 10-DEBC HCl capillary electrophoresis, CE-SDS == Introduction == The target specificity, favorable pharmacokinetics and pharmacodynamics, and stability of monoclonal human immunoglobulin gamma (IgG) antibodies have resulted in their widespread use in the biopharmaceutical industry.1,2Commercial therapeutic antibody production is usually a complex but fairly well established process, typically involving expression in Chinese hamster ovary cells (CHO), harvesting of the secreted protein, and a series of chromatography steps to remove impurities. Reduction of antibody interchain disulfide bonds during manufacturing operations has recently been the subject of much interest.3-5This phenomenon is observed when extending the time that this antibody remains in the cell culture fluid (CCF) or harvested cell culture fluid (HCCF) in the harvest step of production. This harvest step includes separation of cells from the media prior to the first column purification. Process-induced antibody disulfide bond reduction has been observed inconsistently at large scale processes and is not typically observed with standard bench-scale (up to 10 L) models.5This reduction has been attributed to certain enzymes that are released from the intracellular compartments of lysed cells. Components in the thioredoxin reduction pathway, including thioredoxin reductase and NADPH, have been proposed as the principal underlying contributor 10-DEBC HCl for this antibody disulfide bond reduction.3,4Reduction has been shown to be virtually eliminated by maintaining dissolved oxygen (DO) levels during harvest operations.5In addition, the cysteine/cystine redox couple, which is present in the growth media, may affect disulfide bond formation, reduction, and rearrangement.6Likewise, many other media components, such as certain metal ions and their complexes, are likely to affect the reduction potential during the harvest procedure.5,6 In these studies, cell lysis and an anaerobic environment both promoted antibody reduction during 10-DEBC HCl harvest;5,6therefore, it is clear that adequate process understanding and control is necessary to minimize or eliminate disulfide bond reduction induced by manufacturing procedures. In addition to variation due to manufacturing processes, differences between products were observed.5Because cell cultures, cell lines, and the products themselves can vary in cell cultures expressing two different antibody products, the underlying causes for these reduction differences could not be determined. The study presented here explores the relationship between reduction and process variables, separating the influence of process and products to demonstrate that CHO cell line or cell culture process can dramatically influence reduction during harvest operations and that the antibody class and light chain type also influences the extent of that reduction. == Results == == Small scale model == Harvest-related disulfide reduction has been reported as highly dependent on process scale and has been reported in some scaled-up, but not bench-scale, processes.5This effect of scale may be attributed to the maintenance of oxygen in small-scale harvests, which may preserve disulfide bonds. Typically, bench-scale experiments are open to the air, which allows more efficient oxygen transfer than common manufacturing-scale (15,000 to 20,000 L) cell culture production. Bench-scale experiments make use of different centrifuge tools also, introducing the chance of different examples of cell shearing during removal of particles. To facilitate harvest decrease tests, a small-scale model, just like referred to versions previously,5was created. A most severe case decrease style of cell tradition extract was produced by mechanically shearing 2 L of entire cell tradition fluid (CCF) useful for production of the IgG1 mAb (mAb A), moving the sheared CCF right into a 3 L bioreactor, and sparging the resultant slurry with nitrogen to simulate the anaerobic environment from the industrial scales. Samples had been used at 0, 0.5, 1, 2, 4, 8, and 24 h and frozen at -70C. Non-reduced Rabbit Polyclonal to 5-HT-1F capillary electrophoresis with sodium dodecyl sulfate (NR CE-SDS) was performed on all examples to gauge the 10-DEBC HCl amount of interchain disulfide relationship breakage. Consultant electropherograms of the partially.