• Clinical and Experimental Pediatrics
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• v.49 no.4
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• pp.439-445
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• 2006

Purpose : ${\alpha}$-Galactosylceramide (${\alpha}$-GalCer)-stimulated human $V{\alpha}24$ natural killer T (NKT) cells exert antitumor activity against some leukemia in a CD1d dependent and TCR-mediated manner, but could not kill CD1d - negative neuroblastoma (NB) cells. There are few reports about the direct antitumor effect of highly secreted cytokines by these cells on activation. In this study, using a cell-free supernatant (SPN) collected from plate bound hCD1d/${\alpha}$ GalCer tetramers-stimulated NKT cells, we examined whether they could be helpful in the immunotherapeutic treatment of NB. Methods : Cells were cultured in IMDM. The cytokines produced by NKT cells were measured with Cytometric Bead Array (CBA) analysis. Cell viability was evaluated by calcein-AM fluorescence with digital image microscopy scanning (DIMSCAN). The percentage of specific apoptosis was calculated by flow cytometric detection of apoptosis using annexin V and 7-AAD. Results : The activated NKT cells secreted high levels of IL-2, INF-${\gamma}$, TNF-${\alpha}$. The SPN was significantly cytotoxic against four out of eight tested NB cell lines, through mainly apoptosis as evidenced by annexin-V staining and inhibition with the pretreatment of pancaspase blocker. This apoptosis was significantly inhibited when anti-TNF-${\alpha}$ and anti-IFN-${\gamma}$ neutralizing mAbs were used separately and it was completely abolished when the two mAbs were combined. Conclusion : IFN-${\gamma}$ and TNF-${\alpha}$ produced by NKT cells could exert synergistically direct antitumor activity through apoptosis on some NB cell lines.

• IMMUNE NETWORK
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• v.13 no.5
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• pp.218-221
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• 2013

CD1d expressing dendritic cells (DCs) are good glyco-lipid antigen presenting cells for NKT cells. However, resting B cells are very weak stimulators for NKT cells. Although ${\alpha}$-galactosylceramide (${\alpha}$-GalCer) loaded B cells can activate NKT cells, it is not well defined whether B cells interfere NKT cell stimulating activity of DCs. Unexpectedly, we found in this study that B cells can promote Th1-skewed NKT cell response, which means a increased level of IFN-${\gamma}$ by NKT cells, concomitant with a decreased level of IL-4, in the circumstance of co-culture of DCs and B Cells. Remarkably, the response promoted by B cells was dependent on CD1d expression of B cells.