Gangliosides in T Cell Immunity

Abstract

Gangliosides are sialic acid-containing glycosphingolipids and are the main components of lipid rafts, which have important regulatory functions such as cell recognition, ligand–receptor interactions, cell adhesion, and cell growth. Gangliosides are separated into several series on the basis of the absence (o-series) or presence of one (a-series) or two (b-series) sialic acid residues linked to the galactose residue in the second position from ceramide. T cells are central for acquired immunity and, as with gangliosides, are phenotypically divided into several subpopulations. The individual T cell subpopulations have been shown to express differential series of gangliosides: helper T cells and cytotoxic T cells preferentially express a-series and o-series gangliosides respectively, which are responsible for antigen receptor-mediated activation in each T cell subset. Recent studies have shown the abnormal ganglioside expression in T cells from some autoimmune and allergic disorders. GM3 synthase (named St3Gal5) deficiency ameliorates helper T cell-mediated airway hypersensitivity in a mouse model of allergic asthma. Therefore, a variety of lipid rafts with different gangliosides may be formed on the plasma membrane of each T cell subset. This review focuses on the selective role of different gangliosides in T cell activation and immune system disorders.