Galectin-8 binds to LFA-1, blocks its interaction with ICAM-1 and is counteracted by anti-Gal-8 autoantibodies isolated from lupus patients

Biol Res. 2013;46(3):275-80. doi: 10.4067/S0716-97602013000300008.

Abstract

Galectin-8 belongs to a family of mammalian lectins that recognize glycoconjugates present on different cell surface components and modulate a variety of cellular processes. A role of Gal-8 in the immune system has been proposed based on its effects in immune cells, including T and B lymphocytes, as well as the presence of anti-Gal-8 autoantibodies in the prototypic autoimmune disease systemic lupus erythematosus (SLE). We have previously described that Gal-8 induces apoptosis in activated T cells interacting with certain β1 integrins and this effect is counteracted by the anti-Gal-8 autoantibodies. Given that Gal-8 can potentially interact with several glycoproteins, here we analyzed the β2 integrin Lymphocyte Function-Associated Antigen-1 (LFA-1), which is involved in leukocyte cell adhesion and immunological synapses. We show by GST-pull down assays that Gal-8 interacts with LFA-1 and this interaction is inhibited by anti-Gal-8 autoantibodies isolated from SLE patients. In cell adhesion assays, Gal-8 precluded the interaction of LFA-1 with its ligand Intracellular Adhesion Molecule-1 (ICAM-1). These results suggest that Gal-8 can exert immunosuppressive action not only by inducing apoptosis in activated T cells but also by negatively modulating the crucial function of LFA-1 in the immune system, while function-blocking autoantibodies counteract these effects.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antibodies, Monoclonal / immunology
  • Antibodies, Monoclonal / metabolism
  • Autoantibodies / immunology
  • Autoantibodies / metabolism
  • Cell Adhesion
  • Galectins / metabolism*
  • Humans
  • Intercellular Adhesion Molecule-1 / metabolism*
  • Lupus Erythematosus, Systemic / immunology*
  • Lymphocyte Function-Associated Antigen-1 / metabolism*

Substances

  • Antibodies, Monoclonal
  • Autoantibodies
  • Galectins
  • LGALS8 protein, human
  • Lymphocyte Function-Associated Antigen-1
  • Intercellular Adhesion Molecule-1