Pluripotent stem cells such as iPS cells have the potential to develop into any cell type in the adult body. This feature gives them great promise for new regenerative medicine. However, the differentiation protocols to differentiate iPS cells often use animal components, which prohibits the use of the resulting cells in the clinic. A new study by the Megumu Saito laboratory reports the differentiation of natural killer (NK) cells from iPS cells using defined chemical components only. This protocol is expected to advance cancer immunotherapies.

All immune cells including NK cells are believed to derive from human progenitor cells, for which the Saito lab had already established a chemically-defined protocol using iPS cells. To generate NK cells from the human progenitor cells, the scientists optimized conditions using just four chemical factors: SCf, Tlt3L, IL-7 and IL-15. The resulting NK cells showed good anti-cancer properties against leukemia cells both in a dish and in mice. This protocol is expected to advance the clinical translation of iPS cell-derived NK cells. In the future, the ability to produce NK cells from patient iPS cells using this protocol will invite study of related immunodiseases.

• doi: 10.1016/j.bbrc.2019.03.085