Key role of NKT cells and NK cells in the antimetastatic effect of α-GalCer.
Groups of B6 WT, B6 RAG-1−/−, B6 CD1d−/−, B6 Jα281−/− mice, or B6 mice treated with rabbit anti-asGM1 antibody on days −1, 0 (the day of tumor inoculation), and 7 were inoculated (A) intravenously with 5 × 105 B16F10 tumor cells or (B) intrasplenically with 5 × 105 3LL tumor cells. Some groups of mice were treated intraperitoneally with 2 μg α-GalCer (▨) or vehicle control (▪) on days 0, 4, and 8 after tumor inoculation, as indicated. In all experiments, 14 days after tumor inoculation the lungs (B16F10) or livers (3LL) of these mice were harvested, and tumor colonies were counted and recorded as the mean number of colonies ± SE. The number of mice in each group is indicated in parentheses, and asterisks indicate the groups in which α-GalCer treatment significantly reduced that group's number of lung or liver metastases (Mann-Whitney U: *P < .05; **P < .001).
