Nature Biotechnology
17, 1116 - 1121 (1999)
doi:10.1038/15104
Engineering Chinese hamster ovary cells to maximize sialic acid content of recombinant glycoproteinsS. Weikert1, D. Papac2, J. Briggs2, D. Cowfer2, S. Tom1, M. Gawlitzek6, J. Lofgren1, S. Mehta1, V. Chisholm4, N. Modi5, S. Eppler5, K. Carroll1, S. Chamow3, D. Peers3, P. Berman1
& L. Krummen11
Department of Cell Culture and Fermentation Research and Development, Genentech, Inc., South San Francisco, CA 94080. 2
Department of Analytical Chemistry, Genentech, Inc., South San Francisco, CA 94080. 3
Department of Recovery Sciences, Genentech, Inc., South San Francisco, CA 94080. 4
Department of Molecular Biology, Genentech, Inc., South San Francisco, CA 94080. 5
Department of Pharmacokinetics and Metabolism, Genentech, Inc., South San Francisco, CA 94080. 6
Department of Manufacturing Sciences, Genentech, Inc., South San Francisco, CA 94080.
Correspondence should be addressed to L. Krummen krummen.lynne@gene.comglycosylationglycosyltransferase overexpressionrecombinant protein expressionChinese hamster ovary cellsWe have engineered two Chinese hamster ovary cell lines secreting different recombinant glycoproteins to express high levels of human  1,4-galactosyltransferase (GT, E.C. 2.4.1.38) and/or  2,3-sialyltransferase (ST, E.C. 2.4.99.6). N-linked oligosaccharide structures synthesized by cells overexpressing the glycosyltransferases showed greater homogeneity compared with control cell lines. When GT was overexpressed, oligosaccharides terminating with GlcNAc were significantly reduced compared with controls, whereas overexpression of ST resulted in sialylation of  90% of available branches. As expected, GT overexpression resulted in reduction of oligosaccharides terminating with GlcNAc, whereas overexpression of ST resulted in sialylation of 90% of available branches. The more highly sialylated glycoproteins had a significantly longer mean residence time in a rabbit model of pharmacokinetics. These experiments demonstrate the feasibility of genetically engineering cell lines to produce therapeutics with desired glycosylation patterns.
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