Cutting glycolipids down to size

Abstract

http://immunol.nature.com • march 2001 • volume 2 no 3 • nature immunology A surprising development in the field of antigen presentation in recent years has been the demonstration of highly specific T cell responses to self and foreign lipids and glycolipids. This phenomenon is mediated by a family of cell surface proteins called CD1 that function as lipid-binding and presenting molecules expressed on the surface of antigen-presenting cells (APCs). All CD1 proteins appear to contain a hydrophobic pocket that binds the aliphatic chains of the ligands they present. This trapping of an individual lipid or glycolipid ligand in the CD1 protein creates a complex in which the hydrophobic portions of the ligand are buried in the binding pocket of the protein while the hydrophilic cap of the ligand protrudes into the solvent to create a complex epitope that engages specific T cell antigen receptors (TCRs). So far, only a small number of specific lipid or glycolipid antigens presented by this mechanism have been identified. The best studied of these have relatively simple structures that can be envisioned to fit comfortably into the space available between the CD1 protein and the specific TCRs that dock with it. But what of the vast array of glycolipids with complex oligosaccharide or polysaccharide head-groups that exist in microbial pathogens and in mammalian tissues? Might some of these larger complex glycolipids be enzymatically processed to yield smaller glycolipids that would be more suitable for presentation by CD1? A recent study by Prigozy et al. in Science now provides a precedent for this. Their data raises the possibility that the spectrum of CD1-presented antigens includes larger, complex glycolipids that are subjected to partial degradation of their glycans by enzymes expressed in APCs. Cutting glycolipids down to size

DOI: 10.1038/85234

Cite this paper

@article{Porcelli2001CuttingGD, title={Cutting glycolipids down to size}, author={Steven Anthony Porcelli}, journal={Nature Immunology}, year={2001}, volume={2}, pages={191-192} }