The unconventional lifestyle of NKT cells

Many characteristics distinguish CD1d-reactive natural killer T (NKT) cells that express the invariant Valpha14-Jalpha18 T-cell receptor (known here as Valpha14/T cells) from conventional T cells. Because of their apparent self-reactivity, their expression of natural-killer receptors and their capacity to secrete large quantities of cytokines rapidly - including interferon-gamma and interleukin-4 - it has been proposed that Valpha14/T cells might be important for the initiation and regulation of immune responses. New studies are beginning to shed light on the development, selection, homeostasis and possible function(s) of Valpha14/T cells, which are 'non-conformists' compared with the main T-cell populations. These studies might lead to the development of techniques for the controlled manipulation of the Valpha14/T-cell response, which could one day form the basis of immune therapies.