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(2015) Comparison of methods for the analysis of therapeutic immunoglobulin G Fc-glycosylation profiles-Part 1: Separation-based methods, mAbs, 7:1, 167-179, DOI: 10.4161/19420862.2014.986000 To link to this article: https://doi.org/10. 4161/19420862.2014 Abbreviations: mAb, monoclonal antibody; Fc, fragment crystallizable; IgG, immunoglobulin G; HILIC-UPLC, hydrophilic interaction liquid chromatography-ultra high performance liquid chromatography; 2-AB, 2-aminobenzamide; Fab, fragment, antigen-binding; CE-LIF, capillary electrophoresis-laser induced fluorescence; HPLC, high performance liquid chromatography; MALDI-MS, matrix-assisted laser desorption/ionization-mass spectrometry; ESI-MS, electrospray ionization-mass spectrometry; HPAEC-PAD, high-performance anion exchange chromatography with pulsed amperometric detection; APTS, 8-aminopyrene-1, 3, 6-trisulfonic acid; DSA-FACE, DNA-sequencer-aided fluorophore-assisted carbohydrate electrophoresis; ANTS, 8-aminonaphthalene-1, 3, 6-trisulfonate; CCGE, cartridge-based capillary gel electrophoresis; HR, high resolution; IAB, InstantAB labeling; CHO, Chinese hamster ovaryImmunoglobulin G (IgG) crystallizable fragment (Fc) glycosylation is crucial for antibody effector functions, such as antibody-dependent cell-mediated cytotoxicity, and for their pharmacokinetic and pharmacodynamics behavior. To monitor the Fc-glycosylation in bioprocess development, as well as product characterization and release analytics, reliable techniques for glycosylation analysis are needed. A wide range of analytical methods has found its way into these applications. In this study, a comprehensive comparison was performed of separation-based methods for Fcglycosylation profiling of an IgG biopharmaceutical. A therapeutic antibody reference material was analyzed 6-fold on 2 different days, and the methods were compared for precision, accuracy, throughput and other features; special emphasis was placed on the detection of sialic acid-containing glycans. Seven, non-mass spectrometric methods were compared; the methods utilized liquid chromatography-based separation of fluorescent-labeled glycans, capillary electrophoresis-based separation of fluorescent-labeled glycans, or high-performance anion exchange chromatography with pulsed amperometric detection. Hydrophilic interaction liquid chromatography-ultra high performance liquid chromatography of 2-aminobenzamide (2-AB)-labeled glycans was used as a reference method. All of the methods showed excellent precision and accuracy; some differences were observed, particularly with regard to the detection and quantitation of minor glycan species, such as sialylated glycans.

(2015) Comparison of methods for the analysis of therapeutic immunoglobulin G Fc-glycosylation profiles-Part 2: Mass spectrometric methods, mAbs, 7:4, 732-742, DOI: 10.1080DOI: 10. /19420862.2015 To link to this article: https://doi.org/10. 1080/19420862.2015 To monitor the Fc glycosylation of therapeutic immunoglobulin G in bioprocess development, product characterization and release analytics, reliable techniques for glycosylation analysis are needed. Several analytical methods are suitable for this application. We recently presented results comparing detection methods for glycan analysis that are separation-based, but did not include mass spectrometry (MS). In the study reported here, we comprehensively compared MS-based methods for Fc glycosylation profiling of an IgG biopharmaceutical. A therapeutic antibody reference material was analyzed 6-fold on 2 different days, and the methods investigated were compared with respect to precision, accuracy, throughput and analysis time. Emphasis was put on the detection and quantitation of sialic acid-containing glycans. Eleven MS methods were compared to hydrophilic interaction liquid chromatography of 2-aminobenzamide labeled glycans with fluorescence detection, which served as a reference method and was also used in the first part of the study. The methods compared include electrospray MS of the heavy chain and Fc part after limited digestion, liquid chromatography MS of a tryptic digest, porous graphitized carbon chromatography MS of released glycans, electrospray MS of glycopeptides, as well as matrix assisted laser desorption ionization MS of glycans and glycopeptides. Most methods showed excellent precision and accuracy. Some differences were observed with regard to the detection and quantitation of low abundant glycan species like the sialylated glycans and the amount of artefacts due to in-source decay.

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In this study, the advantage of a novel measuring device for the online determination of oxygen and carbon dioxide transfer rates in shaking-flasks is reported for glucose oxidation by Gluconobacter oxydans. In this fermentation process, this device was used for the characterization of the oxidation pattern of different strains. G. oxydans NCIMB 8084 forms 2,5-diketogluconate from d-glucose in a multi-stage process via three different membrane-bound dehydrogenases. This strain was chosen for a scale-up of the process from shaking-flasks to a 2-l stirred vessel. An enhancement of 2,5-diketogluconate production was realized by controlling the pH at different levels during the fermentation.