CD4 and neoplasm: Although not directly killing tumor cells, NKT cells simulate the cross-priming of tumor antigens by DCs through rapid secretion of large amounts of IFN-γ, IL-12, and IP10 (IFN-γ inducible protein 10) and are able to induce further recruitment of NK cells, macrophages, DCs, CD4+ and CD8+ T cells to tumor sites (157).