Enhancing effects of α-, β-monoglycosylceramides on natural killer cell activity Original Research Article

We examined in vitro and in vivo natural killer (NK) cell activity enhancing effects of α-, β-galactosylceramide (GalCer) and α-, β-glucosylceramide (GluCer) which have the same ceramide moiety, and of other α-, β-GalCer having a different ceramide portion, and found that α-types show stronger enhancing effects than β-types and the α-GalCer possesses the most potent activity among GalCers and GluCers having the same ceramide moiety. When the comparison of tumor growth inhibitory effects of α-, β-GalCer on mice subcutaneously inoculated with B16 cells was performed, the α-GalCer showed stronger suppressive activity than its β-type, paralleling their enhancing effects on NK cell activity. These results suggest that the manner of combination between sugar and ceramide plays an important role in antitumor activity as well as enhancing effect on NK cell activity of GalCers.