Figure 6.

PPARγ in DCs modulates Th2 polarization in vivo. (A) The generation of Cd11c-CrePparg^fl/fl mice containing WT AMs is shown schematically. Fetal (E17.5) lung AM precursors from WT CD45.1⁺ C57BL/6 embryos were transferred intranasally to neonatal (day 3 after birth) Pparg^fl/fl and Cd11c-CrePparg^fl/fl mice. After 8 wk, animals showed a reconstitution of Cd11c-CrePparg^fl/fl mice with mature WT AMs, and they were subsequently used in HDM or OVA/alum asthma protocols, as described in Fig. 1 and Fig. S1. (B) Animals were sensitized with HDM and challenged with HDM or PBS with total cell numbers in the BAL (B) and lung (C) of eosinophils and neutrophils (n = 4–8/group). (D, left) Hematoxylin and eosin (H&E) histology. (D, right) PAS and Alcian blue histology. (E) Representative sections of total cell numbers of CD4⁺ and CD8⁺ T cells in the BAL. (F) BAL CD4⁺ T cells were restimulated with PMA/ionomycin for 4 h, and intracellular cytokine production was quantified, with the frequency of indicated cytokines (n = 4–8/group). (G) Total number of lung ILC2s are shown. (H–J) WT and Cd11c-CrePparg^fl/fl mice were sensitized with OVA/alum i.p. and challenged with OVA intratracheally (H). Shown are total cell numbers in the lung of eosinophils and neutrophils (I) and CD4⁺ and CD8⁺ T cells (J). (J) BAL CD4⁺ T cells were restimulated with PMA/ionomycin for 4 h, and intracellular cytokine production was quantified. Frequency of IFN-γ⁺, IL-17A⁺, and IL-4⁺ cells as well as the MFI for IL-4 (n = 5/group). The data are representative of two experiments for each panel and are means ± SEM, with the sample size (n). The Student’s t test (unpaired) was used. *, P < 0.05; **, P < 0.01; ****, P < 0.0001.