Homo sapiens Transcriptome or Gene expression

Group 2 innate lymphoid cells (ILC2s) play critical roles in type 2 immunity. Although their classical activators are host epithelial-derived alarmin cytokines released from damaged tissues at barrier sites during microbial infection and allergen exposure, it remains unclear whether ILC2s can be directly activated by microbial ligands. Here, we found that the abundance of blood endotoxin lipopolysaccharide (LPS) was positively correlated with circulating ILC2s in patients with allergic rhinitis and atopic dermatitis. Furthermore, LPSs were identified from a number of microbial ligands and multiple species of Gram-negative bacteria that potently stimulate cultured ILC2s to proliferate and produce massive amounts of type 2 effector cytokines, including IL-5 and IL-13. RNA-seq revealed a large set of type 2 immune-responsive signature genes in LPS-induced ILC2s.