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. Themajority of theN-glycans of transgenic pigderived
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 detectableNeu5Gc,
the sialic acid commonly found in porcine glycoproteins produced
in other tissues.Additionally,wewere unable to detect
glycans in tg-FIX that have a terminal Galα(1,3)Gal disaccharide
sequence, which is strongly antigenic in humans.
The N-glycan structures of tg-FIX are also compared to the
publishedN-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
