α-Galactosylceramide (KRN7000) is a synthetic glycolipid with antitumorial and immunostimulatory and is a very potent NKT cell agonist and binds effectively to CD1d. The complex of α-Galactosylceramide and CD1d can bind to the T cell antigen receptor of NKT cells.

Stimulation of activated Vα24+ NKT cell cultures with α-Galactosylceramide-pulsed monocyte-derived dendritic cells (Mo-DC) has antiproliferative activity against melanoma cells. Antiproliferative effects of Vα24+ NKT cells stimulated by α-Galactosylceramide-pulsed Mo-DCs via soluble mediators have antitumor activity against human melanoma. This effect is mainly due to the release of IFN-γ and, to a lesser extent, IL-12. Other cytokines, including IL-4 and IL-10, are released, but these cytokines have less antiproliferative effects [2].

α-Galactosylceramide treatment prevents spontaneous, oncogenic, or oncogene-induced primary tumor formation in mice. Consistent with a major role of IFN-γ in NKT cell-mediated tumor responses, the C-glycoside analog of α-Galactosylceramide, which preferentially stimulates IFN-γ production, was even more effective than α-galactose in preventing B16 melanoma metastasis. Ceramides are more effective [1]. α-Galactosylceramide showed potent antitumor activity and stimulated lymphocyte proliferation (LP) in mouse allogeneic mixed lymphocyte reaction (MLR) [4].