Glycobiology Advance Access originally published online on May 2, 2008
Glycobiology 2008 18(7):526-539; doi:10.1093/glycob/cwn035
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Analysis of the N-glycans of recombinant human Factor IX purified from transgenic pig milk
2 Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, Lincoln, NE 68588, USA
3 Progenetics LLC, 1872 Pratt Drive, Suite 1400, Blacksburg, VA 24060, USA
1 To whom correspondence should be addressed: Tel: +1-402-472-1743; Fax: +1-402-472-6989; e-mail: kvancott2{at}unl.edu
Received on October 10, 2007; revised on April 26, 2008; accepted on April 27, 2008
Glycosylation of recombinant proteins is of particular importance because it can play significant roles in the clinical properties of the glycoprotein. In this work, the N-glycan structures of recombinant human Factor IX (tg-FIX) produced in the transgenic pig mammary gland were determined. The majority of the N-glycans of transgenic pig-derived Factor IX (tg-FIX) are complex, bi-antennary with one or two terminal N-acetylneuraminic acid (Neu5Ac) moieties. We also found that the N-glycan structures of tg-FIX produced in the porcine mammary epithelial cells differed with respect to N-glycans from glycoproteins produced in other porcine tissues. tg-FIX contains no detectable Neu5Gc, the sialic acid commonly found in porcine glycoproteins produced in other tissues. Additionally, we were unable to detect glycans in tg-FIX that have a terminal Gal
(1,3)Gal disaccharide sequence, which is strongly antigenic in humans. The N-glycan structures of tg-FIX are also compared to the published N-glycan structures of recombinant human glycoproteins produced in other transgenic animal species. While tg-FIX contains only complex structures, antithrombin III (goat), C1 inhibitor (rabbit), and lactoferrin (cow) have both high mannose and complex structures. Collectively, these data represent a beginning point for the future investigation of species-specific and tissue/cell-specific differences in N-glycan structures among animals used for transgenic animal bioreactors.
Key words: glycoprotein / Factor IX / glycosylation / mammary gland / transgenic animal