Proprionate supplementation increases lung Sema4⁺ moDCs. (a) Sema4a mRNA expression in lung. (b) Sema4a-expressing DC numbers in lung (top) and MLN (bottom). Nrp-1⁺ T reg cell number in lung. (c) Mean fluorescence intensity of CFSE in Nrp1⁺ T reg cells. For panels a and b, data are representative of n = 2 experiments with four to six neonates in each group and are presented as box-and-whisker plots showing quartiles (boxes) and range (whiskers). For panel c, each data point represents a technical replicate and is representative of n = 2 experiments. Data were analyzed by one-way ANOVA with Tukey’s post hoc test; *, P < 0.05; **, P < 0.01; ***, P < 0.001 compared with vehicle-treated pDC^Δ mice (a and b) or unstimulated cells (c).