The synthesis of deoxy-alpha-Gal epitope derivatives for the evaluation of an anti-alpha-Gal antibody binding

Carbohydr Res. 2002 Aug 16;337(14):1247-59. doi: 10.1016/s0008-6215(02)00159-3.

Abstract

Alpha-Gal epitopes (also termed as alpha-Gal) are carbohydrate structures bearing the alpha-D-Gal-(1-->3)-beta-D-Gal terminus 1 and are known to be the antigen responsible for antibody-mediated hyperacute rejection in xenotransplantation. Terminal 2-, 3-, 4-, and 6-deoxy-Gal derivatives of alpha-Gal were synthesized. Inhibition ELISA using mouse laminin was established to determine the binding affinity of the synthesized alpha-Gal derivatives. 4-Deoxy-alpha-Gal derivative 7 showed a significant reduction in antibody recognition. The IC(50) value was 15-fold poorer than the standard alpha-Gal epitopes alpha-D-Gal-(1-->3)-beta-D-Gal-(1-->4)-beta-D-Glc-NHAc (39) and alpha-D-Gal-(1-->3)-beta-D-Gal-(1-->4)-beta-D-Glc-OBn (40). A similar observation was seen with 2-deoxy-alpha-Gal derivative 5, whose IC(50) value was nearly tenfold higher than the standards. Interestingly, substitution at the terminal 3-position resulted in only a fourfold decrease in antibody recognition, suggesting a possible point of future derivation. Finally, 6-deoxy-alpha-Gal derivative 8 exhibited similar antibody recognition to both alpha-Gal epitope 39 and alpha-Gal epitope 40. This strongly suggests that derivatization at the 6-position can be accomplished without loss of antibody recognition. These findings can be utilized for the future design of other alpha-Gal derivatives.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies*
  • Carbohydrate Conformation
  • Carbohydrate Sequence
  • Disaccharides / chemical synthesis*
  • Disaccharides / chemistry
  • Epitopes / immunology
  • Fucose / chemical synthesis*
  • Fucose / immunology*
  • Galactose
  • Molecular Sequence Data
  • Oligosaccharides / chemical synthesis*
  • Oligosaccharides / chemistry

Substances

  • Antibodies
  • Disaccharides
  • Epitopes
  • Oligosaccharides
  • Fucose
  • Galactose