Unconventional ST2- and CD127-negative lung ILC2 populations are induced by the fungal allergen Alternaria

Group 2 innate lymphoid cells (ILC2s) have been recognized for their ability to drive type 2 responses in experimental animal models in the absence of T cells. Mice intranasally challenged with Alternaria alternata, a fungal allergen associated with severe asthma and fatal exacerbations in humans, potently activates ILC2s via the IL-33/ST2 (IL-33R) axis to robustly secrete type 2 cytokines. Animal models, including Alternaria-induced lung inflammation in mice, have given us critical insight into pathways of ILC2 regulation that appear to apply to ILC2 responses in human disease.7 Thus, accurate identification of ILC2s in the lungs of mice is critical to future understanding of their biology and contribution to allergic disease. We assessed whether the conventional ILC2 identification markers ST2 and CD127.