IL-25–mediated induction of MPP^type2 cells occurs independently of Id2. (a–p) CD5/B220-depleted donor BM (WT, CD45.1; Id2^−/−, CD45.1.2) was transferred into lethally irradiated C57BL/6 WT (CD45.2) mice. After reconstitution for 8 wk after transplant, mice were treated i.p. with PBS (control), 0.3 µg of recombinant IL-33, or 0.3 µg of recombinant IL-25 daily for 7 d. MLNs were harvested, and the frequency and total cell numbers of ILC2 and MPP^type2 cells were assessed by flow cytometry. (a and c) Frequency of T1/ST2^pos IL-7Rα^pos ILC2 from control or IL-33–treated WT BM chimera mice (a) or Id2-deficient BM chimera mice (c). (b and d) Total cell numbers of ILC2 from control or IL-33–treated WT BM chimera mice (b) or Id2-deficient BM chimera mice (d). (e and g) Frequency of c-kit^pos MPP^type2 cells from control or IL-33–treated WT BM chimera mice (e) or Id2-deficient BM chimera mice (g). (f and h) Total cell numbers of MPP^type2 cells from control or IL-33–treated WT BM chimera mice (f) or Id2-deficient BM chimera mice (h). (i and k) Frequency of T1/ST2^pos IL-7Rα^pos ILC2 cells from control or IL-25–treated WT BM chimera mice (i) or Id2-deficient BM chimera mice (k). (j and l) Total cell numbers of ILC2 from control or IL-25–treated WT BM chimera mice (j) or Id2-deficient BM chimera mice (l). (m and o) Frequency of c-kit^pos MPP^type2 cells from control or IL-25–treated WT BM chimera mice (m) or Id2-deficient BM chimera mice (o). (n and p) Total cell numbers of MPP^type2 cells from control or IL-25–treated WT BM chimera mice (n) or Id2-deficient BM chimera mice (p). Plots are gated on live, Lin^neg (CD4, CD8, CD11b, CD11c, and CD19) donor-derived cells. Data in a–p are representative of two or more independent experiments (control, n = 4; IL-33 treated, n = 6; IL-25 treated, n = 6). Error bars indicate SEM.