CD1a-binding glycosphingolipids stimulating human autoreactive T-cells: synthesis of a family of sulfatides differing in the acyl chain moiety

Native sulfatide (a mixture of 3-sulfated β-d-galactopyranosylceramides with different fatty acids at the ceramide moiety) is an antigen presented by CD1a proteins. Herein the preparation of four sulfatides, which are constituents of the natural mixture and bear palmitic, stearic, behenic or nervonic fatty acid chains, is described. Azidosphingosine was stereoselectively synthesized through a CuCN-catalyzed allylic alkylation of a hexenitol dimesylate derived from d-xylose; β-glycosylation of azidosphingosine with a suitable d-galactosyl trichloroacetimidate led, after reduction of the azido group, to the galactosylsphingosine skeleton, which was derivatized with the different fatty acids. Final regioselective 3-sulfation gave the desired sulfatides, which were tested for activation of sulfatide-specific and CD1a-restricted T-cell clones.