Syntheses of biotinylated alpha-galactosylceramides and their effects on the immune system and CD1 molecules

A representative alpha-galactosylceramide (alpha-GalCer), KRN7000, has stro ng immunostimulatory and antitumor activity. Recent studies demonstrated th at KRN7000-pulsed antigen-presenting cells (APC) can activate natural kille r T (NKT) cells, a novel T-cell lineage, and CD1d molecules on APC play an important role in the activation of NKT cells. However, it remains unclear whether alpha-GalCers actually bind to CD1d molecules. To address this ques tion, we synthesized three kinds of biotinylated alpha-GalCer and a biotiny lated beta-GalCer and found that the biotinylated alpha-GalCers significant ly stimulate the proliferation of murine spleen cells, but the biotinylated beta-GalCer does not and that all biotinylated compounds bind to CD1d mole cules.