Cell wall glycosphingolipids of Sphingomonas paucimobilis are CD1d-specific ligands for NKT cells.
The current consensus on characterization of NKT cells is based on their reactivity to the synthetic glycolipid, alpha-galactosylceramide (alpha-GalCer) in a CD1d-dependent manner. Because of the limited availability of alpha-GalCer, there is a constant search for CD1d-presented ligands that activate NKT cells. The alpha-anomericity of the carbohydrate is considered to be an important requisite for the CD1d-specific activation of NKT cells. The gram-negative, lipopolysaccharide-free bacterium Sphingomonas paucimobilis is known to contain glycosphingolipids (GSL) with alpha-anomeric sugars attached to the lipid chain. Here, we report that GSL extracted from this bacterium are able to stimulate NKT cells in a CD1d-specific manner. In addition, soluble CD1d-Ig dimers loaded with this lipid extract specifically bind to NKT cells (but not conventional T cells). Further studies on the S. paucimobilis GSL could potentially lead to other natural sources of CD1d-specific ligands useful for NKT cell analyses and aimed at identifying novel therapies for a variety of disease states.
Sriram
Venkataraman
V
Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis 46202-5254, USA.
Du
Wenjun
W
Gervay-Hague
Jacquelyn
J
Brutkiewicz
Randy R
RR
D000818:Animals; D017951:Antigen Presentation; D018949:Antigens, CD1 / Q000378:metabolism*; D055610:Antigens, CD1d; D002460:Cell Line; D002473:Cell Wall / Q000737:chemistry; D002518:Ceramides / Q000378:metabolism; D006028:Glycosphingolipids / Q000378:metabolism*; D006801:Humans; D007694:Killer Cells, Natural / Q000276:immunology / Q000378:metabolism*; D008024:Ligands; D008213:Lymphocyte Activation; D051379:Mice; D008810:Mice, Inbred C57BL; D020578:Sphingomonas / Q000737:chemistry*
D018949:Antigens, CD1; D055610:Antigens, CD1d; C526877:CD1D protein, human; D002518:Ceramides; D006028:Glycosphingolipids; D008024:Ligands