Group 2 innate lymphoid cells (ILC2 cells) are important in immune responses at barrier surfaces, but the factors that control their development are still being identified. In the Journal of Experimental Medicine, two papers by McKenzie and colleagues and Liu and colleagues identify the transcription factor Bcl-11b as being critical for commitment to the ILC2 lineage. The authors find that much like T cells, ILC2 cells have high expression of Bcl-11b in all tissue compartments examined, including in ILC2 progenitors in the bone marrow and mature ILC2 cells in the gut and lungs. Deficiency in Bcl-11b results in an almost total loss of ILC2 cells and, consequently, impaired type II allergic responses and the ability to clear gut helminths. In contrast, the absence of Bcl-11b leads to a greater number of ILC3 cells and intact function. Bcl-11b therefore has an essential cell-intrinsic role in commitment to the ILC2 lineage.

J. Exp. Med. (11 May 2015) doi:10.1084/jem.20142224 & doi:10.1084/jem.20142318