IgA1 is the premier serum glycoprotein recognized by human galectin-1 since T antigen (Galbeta1-->3GalNAc-) is far superior to non-repeating N-acetyl lactosamine as ligand

Int J Biol Macromol. 2005 Jun;35(5):269-76. doi: 10.1016/j.ijbiomac.2005.03.004. Epub 2005 Apr 25.

Abstract

Human heart galectin-1 (HHL) was separated by high pressure liquid chromatography from endogenous glycoproteins co-purified with it during affinity chromatography. These glycoproteins offered excellent ligands for HHL binding and were rich in T antigen (Galbeta1-->3 GalNAc-) of O-linked oligosaccharides. In enzyme linked lectin assay and hemagglutination inhibition assay, human IgA1, bovine fetuin and other O-glycosylated T antigen-bearing glycoproteins bound to the lectin efficiently in contrast to single N-acetyl lactosamine (LacNAc)-bearing N-linked oligosaccharides released from them and to IgG which is not O-glycosylated. HHL binding to IgA1 and fetuin was unaffected by removal of their N-linked oligosaccharides by alpha-mannosidase. When immobilized, O-glycosylated serum proteins but not IgG could capture HHL from its solutions. Desialylated or polymeric IgA1 was better inhibitor than monomeric IgA1. The findings suggest a possible role for galectin-1 in anchoring of microbial and cancer cells known to be rich in T antigen, in high serum IgA1 turn over and in tissue sequestering of IgA1 immune complexes especially after their microbial desialylation in IgA nephropathy and other immune complex-mediated disorders.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acetylgalactosamine / analogs & derivatives
  • Acetylgalactosamine / metabolism
  • Antigens, Tumor-Associated, Carbohydrate / immunology
  • Antigens, Tumor-Associated, Carbohydrate / metabolism*
  • Asialoglycoproteins / metabolism
  • Chromatography, Affinity
  • Chromatography, High Pressure Liquid
  • Electrophoresis, Polyacrylamide Gel
  • Galectin 1 / chemistry
  • Galectin 1 / immunology
  • Galectin 1 / isolation & purification
  • Galectin 1 / metabolism*
  • Humans
  • Immunoglobulin A / immunology
  • Immunoglobulin A / metabolism*
  • Ligands
  • Neuraminidase / metabolism
  • Oligosaccharides / metabolism
  • Plant Lectins / metabolism
  • alpha-Mannosidase / metabolism

Substances

  • Antigens, Tumor-Associated, Carbohydrate
  • Asialoglycoproteins
  • Galectin 1
  • Immunoglobulin A
  • Ligands
  • Oligosaccharides
  • Plant Lectins
  • asialo-galactosyl-acetylgalactosamine
  • jacalin
  • Thomsen-Friedenreich antigen
  • Neuraminidase
  • alpha-Mannosidase
  • Acetylgalactosamine