Figure 1.

Thymic ILC2s are traced with tdTomato expression induced by the plck-Cre transgene. (a) Representative gating strategies for analyses of tdTomato expression in ILC2s from plck-Cre; ROSA26-stop-tdTomato reporter mice. Cells from indicated organs were stained for lineage markers together with antibodies against Thy1 and ST2 (except skin and small intestine). Live CD45⁺ cells were gated before lineage analysis. To ensure the elimination of any contamination of T lineage cells, the Lin⁻ population of each organ was further gated for TCRβ⁻γδTCR⁻ based on staining with antibodies conjugated with different fluorophores from those used for lineage staining. The resulting population was then analyzed for Thy1 and ST2, and the double-positive cells were considered ILC2s (except skin and small intestine). For skin and small intestine cells, Lin⁻Thy1.2⁺CD103⁺ICOS⁺ and Lin⁻Thy1.2⁺GATA3⁺RORγt⁻ populations, respectively, were defined as ILC2s. The bar graph at the bottom shows the average percentages of tdTomato⁺ ILC2 cells from pooled data of several experiments, and the number of each organ analyzed is as indicated. (b) Representative organs of plck-Cre; ROSA26-stop-tdTomato; E2A^f/f; HEB^f/f mice were analyzed as described for panel a (n = 4 for each organ). (c) Percentage of ILC2s of total CD45⁺ cells in indicated organs of mice shown (a) and quantified for statistical analysis (b). Student’s t test was used to determine statistical significance for each organ. Error bars are SEM. **, P < 0.01; ****, P < 0.0001. Thy, thymus; WAT, white adipose tissue; SiLP, small intestine lamina propria.