Constraints on the transport and glycosylation of recombinant IFN-gamma in Chinese hamster ovary and insect cells

Hooker, Andrew D. and Green, Nicola H. and Baines, Anthony J. and Bull, Alan T. and Jenkins, Nigel and Strange, Philip G. and James, David C. (1999) Constraints on the transport and glycosylation of recombinant IFN-gamma in Chinese hamster ovary and insect cells. Biotechnology and Bioengineering, 63 (5). pp. 559-572. ISSN 0006-3592. (The full text of this publication is not currently available from this repository. You may be able to access a copy if URLs are provided)

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In this study we compare intracellular transport and processing of a recombinant glycoprotein in mammalian and insect cells. Detailed analysis of the N-glycosylation of recombinant human IFN-V by matrix-assisted laser-desorption mass spectrometry showed that the protein secreted by Chinese hamster ovary and baculovirus-infected insect Sf9 cells was associated with complex sialylated or truncated tri-mannosyl core glycans, respectively. However, the intracellular proteins were predominantly associated with high-mannose type oligosaccharides (Man-6 to Man-g) in both cases, indicating that endoplasmic reticulum to cis-Golgi transport is a predominant rate-limiting step in both expression systems. In CHO cells, although there was a minor intracellular subpopulation of sialylated IFN-gamma glycoforms identical to the secreted product (therefore associated with late-Golgi compartments or secretory vesicles), no other intermediates were evident. Therefore, anterograde transport processes in the Golgi stack do not limit secretion. In Sf9 insect cells, there was no direct evidence of post-ER glycan-processing events other than core fucosylation and de-mannosylation, both of which were glycosylation site-specific. To investigate the influence of nucleotide-sugar availability on cell-specific glycosylation, the cellular content of nucleotide-sugar substrates in both mammalian and insect cells was quantitatively determined by anion-exchange HPLC. In both host cell types, UDP-hexose and UDP-N-acetylhexosamine were in greater abundance relative to other substrates. However, unlike CHO cells, siaiyltransferase activity and CMP-NeuAc substrate were not present in uninfected or baculovirus-infected Sf9 cells. Similar data were obtained for other insect cell hosts, Sf21 and Ea4. We conclude that although the limitations on intracellular transport and secretion of recombinant proteins in mammalian and insect cells a re similar, N-glycan processing in Sf insect cells is limited, and that genetic modification of N-glycan processing in these insect cell lines will be constrained by substrate availability to terminal galactosylation. (C) 1999 John Wiley & Sons, Inc.

Item Type: Article
Uncontrolled keywords: interferon; N-glycosylation; insect cells; CHO cells; mass spectrometry; nucleotide sugars; secretion
Subjects: Q Science
Divisions: Faculties > Science Technology and Medical Studies > School of Biosciences
Depositing User: I.T. Ekpo
Date Deposited: 20 Apr 2009 19:50
Last Modified: 16 Apr 2014 15:18
Resource URI: (The current URI for this page, for reference purposes)
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