Affinity of monoclonal antibodies for Globo-series glycans

Carbohydr Res. 2014 Oct 9;397:1-6. doi: 10.1016/j.carres.2014.07.003. Epub 2014 Jul 14.

Abstract

Globo-series glycans are human cell-surface carbohydrates that include stem-cell marker SSEA-4 and cancer-cell antigen Globo H. These two hexasaccharides differ only in their terminal saccharide: N-acetylneuraminic acid in SSEA-4 and L-fucose in Globo H. Herein, we evaluated the affinity of the monoclonal antibodies α-SSEA-4 and α-GH for the glycans SSEA-4 and Globo H. Using fluorescence polarization, we find that the two monoclonal antibodies have affinity for their cognate glycan in the low nanomolar range, and have negligible affinity for the non-cognate glycan. Using surface plasmon resonance, we find that each cognate affinity is ∼20-fold greater if the glycan is immobilized on a surface rather than free in solution. We conclude that the terminal saccharide plays a dominant role in the ability of monoclonal antibodies to recognize these Globo-series glycans and that the extraordinary specificity of these antibodies supports their use for identifying and sorting stem-cells (α-SSEA-4) and as an agent in cancer immunotherapy (α-GH).

Keywords: Cancer-cell antigen; Globo H; Globo-series glycan; Monoclonal antibody; SSEA-4; Stem-cell marker.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Antibodies, Monoclonal / immunology*
  • Antibody Specificity
  • Antigens, Tumor-Associated, Carbohydrate / chemistry
  • Antigens, Tumor-Associated, Carbohydrate / immunology*
  • Boron Compounds / chemistry
  • Fluorescence Polarization
  • Humans
  • Solutions
  • Stage-Specific Embryonic Antigens / chemistry
  • Stage-Specific Embryonic Antigens / immunology*
  • Surface Plasmon Resonance

Substances

  • 4,4-difluoro-4-bora-3a,4a-diaza-s-indacene
  • Antibodies, Monoclonal
  • Antigens, Tumor-Associated, Carbohydrate
  • Boron Compounds
  • Globo-H
  • Solutions
  • Stage-Specific Embryonic Antigens
  • stage-specific embryonic antigen-4