Il17rb-CreERT2-eGFP Tg mice allow efficient lineage tracing of ILC2. (A) Schematic representation of the genetic modification in Il17rb-CreERT2-eGFP mice, with a corresponding representative image of the SI showing eGFP-expressing cells (red arrows). Scale bar = 50 μm. (B) Representative flow cytometry plots demonstrating Il17rb-eGFP⁺ expression by SI-LP cells. (C) Representative histograms displaying marker expression by Il17rb-eGFP⁺ cells in the SI. (D) Histograms illustrating eGFP expression by ILC2s across various tissues. Small intestinal ILC2s were defined as Lineage⁻CD127⁺IL-25R⁺KLRG1⁺ cells. Lung ILC2s were defined as Lineage⁻CD127⁺ST2⁺ cells. Skin ILC2s were defined as Lineage⁻CD127⁺CD103⁺ cells. mLN ILC2s were defined as Lineage⁻CD127⁺IL-25R⁺ cells. Muscle ILC2s were defined as Lineage⁻CD127⁺KLRG1⁺ cells. (E) Quantification of Il17rb-eGFP⁺ ILC2s in the SI, mLN, lungs, skin, and muscle (n = 3 mice). (F) Flow cytometry plots showing Il17rb-eGFP⁺ expression in Lineage⁻CD127⁺NK1.1⁺NKp46⁺ ILC1s and Lineage⁻CD127⁺RORγt⁺ ILC3s from Il17rb-CreERT2-eGFP mice. (G) Quantification of Il17rb-eGFP⁺ cells within ILC1s, IL-25R⁺KLRG1⁺ ILC2s, ILC3s, CD4⁺TCRβ⁺ and CD8⁺TCRβ⁺ T cells, and CD45⁺TCRγδ⁺ cells relative to ILC2s in the lungs, skin, and SI (n = 3 mice). (H) Flow cytometry analysis of Il17rb-eGFP⁺ cells in BM from naïve Il17rb-CreERT2-eGFP mice. (I) Quantification of Il17rb-eGFP⁺ cells among adult and neonatal ILC2s compared with adaptive T cell lineages in the BM (n = 3 mice). Data from all panels are representative of three or more independent experiments. Data are means ± SEM. Lineage markers: CD3ε, CD3, CD5, CD8α, TCRβ, Cd11b, CD11c, CD19, B220, Ly6C, Ly6G, Ter119.