Medulloblastoma (MB) is the most common brain tumor of childhood. Current therapies are toxic and often not curative that necessitates development of targeted immunotherapy. However, little is known about immunobiology of this tumor. In this study, we show that MB cells in 9 of 20 primary tumors express CD1d, an antigen-presenting molecule for Natural Killer T cells (NKTs). Quantitative RT-PCR analysis of 61 primary tumors revealed a high level of CD1d mRNA expression in a molecular subgroup characterized by overactivation of Sonic Hedgehog (SHH) oncogene. CD1d-positive MB cells cross-presented glycolipid antigens to activate NKT-cell cytotoxicity. Intracranial injection of human NKTs resulted in regression of orthotopic MB xenografts in NOD/SCID mice. Importantly, the numbers and functional properties of peripheral blood type-I NKTs were preserved in MB patients. Therefore, CD1d is expressed on tumor cells in a subset of MB patients and represents a novel target for immunotherapy of this brain tumor.
- Copyright © 2013 by The American Association of Immunologists, Inc.