Method of producing induced T-to-Natural-Killer [ITNK] cells, target T cells and/or target pro-T cells from T cells and/or pro-T cells which method involves modulating the activity and/or effect of at least one Bcl11b gene and/or protein present in a T cell and/or pro-T cell, and converting said T cell and/or pro-T cell to an ITNK cell or target Tcells and/or target pro-T cells is described. ITNK cells, target T cells and/or target pro-T cells produced by such method and mature activated T cells in which Bcl11b expression is downregulated or absent, and the use of such cells or modulators of Bcl11b in medicine is also described.
