Fig. 4: GM-CSF promotes the development of lung CD301b⁺ cDC2s.

a Surface display level of CSF2Rα on lung cDC2 subsets at steady state and 16 h after OVA/HDE inhalation were analyzed by flow cytometry (n = 4 biological replicates). b GM-CSF level in lung homogenates was measured by ELISA (C57BL/6 n = 7, Csf2^fx n = 6, Csf2^ΔARE n = 8 biological replicates). c–f The frequencies of cDC1s and cDC2 subsets in mouse lungs were analyzed by flow cytometry at steady state (c-e, C57BL/6 n = 7, Csf2^fx n = 6, Csf2^ΔARE n = 8 biological replicates) or after OVA/HDE inhalation (f, C57BL/6 n = 4, Csf2^fx n = 12, Csf2^ΔARE n = 9 biological replicates). (e, f) Representative cytograms (left panels) and compiled data (right panels) of Ly6C^– cDC2s are shown. Gating strategy depicted in Fig. S7a. g Lung cells were harvested and stained from mice at steady state. Activated CD4⁺ T cells (left), representative cytograms of CD4⁺CD44^hi T cells (middle) and compiled data of Tregs (right) (Csf2^fx n = 9, Csf2^ΔARE n = 8 biological replicates). h Representative image of an alveolar duct in a mouse lung analyzed by a laser-scanning microscope. Individual signals for CD301b (green), CD11c (red), F4/80 (grey), and E-cadherin (blue) are shown, as well as a merged image. Arrows indicate CD11c⁺CD301b⁺F4/80^– cells. Scale bar represents 50 μm. a–g Data are presented as mean values ± SEM. Each dot represents an individual mouse. Representative data from two experiments (h) or combined data from two experiments (a–g) are shown. a–f Data were analyzed by one-way ANOVA with Tukey’s multiple comparison test. g Data were analyzed by two-tailed unpaired t-test. P values are indicated above the graphs. Source data are provided as a Source Data file. GM-CSF granulocyte macrophage colony stimulating factor cDC conventional dendritic cells, OVA ovalbumin, HDE house dust extract, ELISA enzyme-linked immunosorbent assay, Treg regulatory CD4⁺ T cells, AD alveolar duct.