Production of a sialylated N-linked glycoprotein in insect cells

Under High Aspect Ratio Vessel (HARV) bioreactor culture conditions designe d to simulate the microgravity of orbital space flight, insect tissue cultu re cells infected with a baculovirus expression vector produced a human gly coprotein with tri- and tetra-antennary complex N-linked oligosaccharides c ontaining terminal sialic acid residues. The oligosaccharide structures wer e similar to those produced in human placental cells. Insect cells cultured in T-flasks only performed incomplete oligosaccharide processing. The mech anism of HARV-mediated changes in the eukaryotic N-linked glycosylation pat hway was investigated and could be mimicked under T-flask growth conditions with the addition of N-acetylmannosamine to the culture medium. The signif icance of these investigations is discussed with respect to the production of recombinant therapeutic glycoproteins, insect physiology, and orbital sp ace flight.