Fig. 3: Breast milk derived factors contribute to the effects of microbiota on neonatal ILC2s.

a Schematic diagram of cross-fostering experiments: pups born to antibiotic dams and control littermates were switched at postnatal day 1 (P1) (n = 5). The phenotype of ILC2 in lungs and allergic airway inflammation were evaluated (b–f). b Flow cytometric analysis of ILC2s in neonatal lungs. c Flow cytometric analysis of the frequency of proliferative ILC2s (Ki-67⁺) and cytokine-producing ILC2s (IL-5⁺IL-13⁺). d Amounts of IL-5 and IL-13 in lung homogenates were determined by ELISA. e Flow cytometric analysis of eosinophils in lungs. f H&E staining of lung tissues (bar, 100 µm) and the histological scoring. In Fig. 3d, the data are presented as the mean ± SEM values, by unpaired two-tailed Student’s t test. For box plots, the data are shown as “Min to Max, show all points”. For box plots, the midline represents the median; box represents the interquartile range (IQR) between the first and third quartiles, and whiskers represent the lowest or highest values within 1.5 times IQR from the first or third quartiles (b, c, e, f). *P < 0.05; **P < 0.01; ***P < 0.001; ****P < 0.0001 by unpaired two-tailed Student’s t test. Data are presentative of 2-3 independent experiments (a–f). Statistical source data are provided in Source Data.