STRUCTURAL CHARACTERIZATION OF N-LINKED AND O-LINKED OLIGOSACCHARIDESDERIVED FROM INTERFERON-ALPHA-2B AND INTERFERON-ALPHA-14C PRODUCED BYSENDAI-VIRUS-INDUCED HUMAN PERIPHERAL-BLOOD LEUKOCYTES

We have previously isolated and partially characterised the components of a highly purified interferon-alpha (IFN-alpha) preparation produce d by Sendai-virus-induced human peripheral blood leukocytes. Nine IFN- alpha species were identified, and two of these were found to be glyco sylated [Nyman, T. A., Tolo, H., Parkkinen, J. & Kalkkinen, N. (1998) Identification of nine interferon-alpha subtypes produced by Sendai-vi rus-induced human peripheral blood leukocytes, Biochem. J. 329, 295-30 2]. Here, we isolated the N-linked oligosaccharides of IFN-alpha 14c a nd the O-linked chains of IFN-alpha 2b, and the glycans were character ised by electrospray tandem mass spectrometry and by specific glycosid ase digestions monitored by matrix-assisted laser desorption ionisatio n time of flight mass spectrometry The IFN-alpha 14c N-glycans were sh own to exhibit core-fucosylated biantennary glycans, with about 10% ca rrying an additional alpha 1,3-linked fucose unit at the antennae. The IFN-alpha 2b was shown to carry about 50% core type-1 disialyltetrasa ccharides, 30% core type-1 monosialyltrisaccharides and 20% core type- 2 monosialylpentasaccharides.