Pharmaceutical Research

, Volume 15, Issue 4, pp 641–649

Structural and Functional Differences Between Glycosylated and Non-glycosylated Forms of Human Interferon-β (IFN-β)

  • Laura Runkel
  • Werner Meier
  • R. Blake Pepinsky
  • Michael Karpusas
  • Adrian Whitty
  • Kathleen Kimball
  • Margot Brickelmaier
  • Celine Muldowney
  • Wendy Jones
  • Susan E. Goelz
Article

DOI: 10.1023/A:1011974512425

Cite this article as:
Runkel, L., Meier, W., Pepinsky, R.B. et al. Pharm Res (1998) 15: 641. doi:10.1023/A:1011974512425

Abstract

Purpose. Two recombinant IFN-β products have been approved for the treatment of multiple sclerosis, a glycosylated form with the predicted natural amino acid sequence (IFN-β-la) and a non-glycosylated form that has a Met-1 deletion and a Cys-17 to Ser mutation (IFN-β-lb). The structural basis for activity differences between IFN-β-la and IFN-β-lb, is determined.

Methods. In vitro antiviral, antiproliferative and immunomodulatory assays were used to directly compare the two IFN-β products. Size exclusion chromatography (SEC), SDS-PAGE, thermal denaturation, and X-ray crystallography were used to examine structural differences.

Results. IFN-β- la was 10 times more active than IFN-β- Ib with specific activities in a standard antiviral assay of 20 × 107 lU/mg for IFN-β-la and 2 × 107 lU/mg for IFN-β-lb. Of the known structural differences between IFN-β-la and IFN-β-lb, only glycosylation affected in vitro activity. Deglycosylation of IFN-β-la produced a decrease in total activity that was primarily caused by the formation of an insoluble disulfide-linked IFN precipitate. Deglycosylation also resulted in an increased sensitivity to thermal denaturation. SEC data for IFN-β-lb revealed large, soluble aggregates that had reduced antiviral activity (approximated at 0.7 × 107 lU/mg). Crystallographic data for IFN-β-la revealed that the glycan formed H-bonds with the peptide backbone and shielded an uncharged surface from solvent exposure.

Conclusions. Together these results suggest that the greater biological activity of IFN-β-la is due to a stabilizing effect of the carbohydrate on structure.

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Copyright information

© Plenum Publishing Corporation 1998

Authors and Affiliations

  • Laura Runkel
    • 1
  • Werner Meier
    • 1
  • R. Blake Pepinsky
    • 1
  • Michael Karpusas
    • 1
  • Adrian Whitty
    • 1
  • Kathleen Kimball
    • 1
  • Margot Brickelmaier
    • 1
  • Celine Muldowney
    • 1
  • Wendy Jones
    • 1
  • Susan E. Goelz
    • 1
  1. 1.Biogen, Inc.Cambridge