CD1D and neoplasm: However, cross-presentation of tumor glycolipids by antigen-presenting cells (APCs) may also play an important role in iNKT-cell activation since some entities show low or no CD1d expression: presentation of glycolipids via CD1d on APCs stimulates iNKT cells to produce cytokines such as IFN-γ and IL-2 that subsequently activate NK cells and tumor-specific T cells (39).