Monitoring the glycosylation pattern of recombinant interferon-omega with high-pH anion-exchange chromatography and capillary electrophoresis.

The enzymatic glycosylation of certain asparagine residues in the protein structure has a profound influence on their physico-chemical properties. Many recombinant DNA derived glycoprotein pharmaceuticals for therapeutic use are glycosylated. Their oligosaccharides are important with regard to stability, solubility, in vivo activity and antigenicity. Sophisticated analytical methods that allow a high resolution of synthesized carbohydrate structures are therefore necessary to ensure a constant product quality. To elucidate the robustness of interferon-omega glycosylation regarding process modifications. Chinese Hamster Ovary (CHO)-cells expressing human interferon-omega were cultivated under different fermentation conditions. The most significant glycosylation alterations resulted from the varied parameters such as initial ammonia concentration in the production medium, cultivation mode (adherent versus suspended) or process time. These are detectable with HPAEC (high-pH anion-exchange chromatography) oligosaccharide mapping as well as with capillary electrophoresis.