Nrp-1⁺ T reg cell restoration prevents the development of PVM-induced bronchiolitis. (a) Protocol of acute PVM infection/pDC depletion and Nrp-1⁺ T reg adoptive transfer 5 dpi (30,000 Nrp-1/Foxp3-RFP⁺ T reg cells, Foxp3-RFP⁻ T con or vehicle diluent; intranasal route). (b and n) Sloughing of the airway epithelium. (c) IL-6 protein expression in the lung. (d and o) Neutrophil number in BAL. (e, l, and p) Eosinophil number in BAL. (g) IL-33 expression in BALF. (h) Nuclear to cytoplasmic HMGB1 translocation in AECs. (f and m) IL-13 expression in BALF. (i) Viral load in the airway epithelium. (j) AHR. (k) ASM area. Data are representative of n = 2 experiments with four to six neonates in each group and are presented as the mean ± SEM (j) or box-and-whisker plots showing quartiles (boxes) and range (whiskers; b–i and k–p). Data were analyzed by one-way (b–i and k–p) or two-way (j) ANOVA with Tukey’s post hoc test; *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with WT mice or as indicated; ^#, P < 0.05; ^##, P < 0.01 compared with pDC^Δ mice.