Natural Killer T cells are a lymphoid population distinct from natural killer cells and conventional T cells. NKT cells recognize lipid antigen in the context of CD1 molecules, unlike classical T cells, which recognize peptide antigens presented by MHC class I and class II molecules. Similar to innate immune cells, NKT cells rapidly mediate their effector functions following activation and help activate other immune cells. Type I NKT cells, also known as canonical or invariant NKT (iNKT) cells express a specific TCRÎ± chain rearrangement, namely VÎ±14JÎ±18 in mice and VÎ±24JÎ±18 in humans, which is associated with VÎ² chains of limited diversity. Type II NKT cells are CD1d-restricted T cells that express diverse TCRs. iNKT cells are further classified into CD4+ and CD4-CD8- double negative (DN) populations in mice whereas human NKT cells are CD4+, CD8+ or DN. It is thought that CD4+ type I NKT cells produce both Th1 and Th2 cytokines such as IFN-Î³ and IL-4, respectively, whereas DN type I NKT cells primarily produce Th1-type cytokines. Moreover, studies have shown that type I NKT cells exert potent anti-tumor effects, whereas type II NKT cells suppress anti-tumor immune responses through their production of Th2 cytokines, namely IL-4 and IL-13. This review will focus mainly on canonical, type I iNKT cells.
Natural Killer T Cell Based Immunotherapy: Priyanka B Subrahmanyam, Wenji Sun, James E East, Junxin Li and Tonya J Webb
Last date updated on July, 2014