Figure 4. AEC GM-CSF is required for CD103⁺ DC activation and migration to draining MLNs under steady-state conditions and upon PR8 infection.

(A and B) WT, Gm-csf^–/–, SPC-GM, WT→Gm-csf^–/–, and Gm-csf^–/–→WT mice were PR8 infected, and the fractions of CD11b⁺ DCs (A) and CD103⁺ DCs (B) in MLNs were quantified by flow cytometry using the gating strategy in C (red gates, CD103⁺ DCs; blue gates, CD11b⁺ DCs). (D) Migratory CD103⁺ DCs from LH of WT mice were additionally stained for IV NP or control IgG at 5 dpi. Representative FACS plot depicts the NP⁺ fraction of CD45⁺CD11c⁺MHCII^hiCD103⁺ DCs. (E) Comparative flow cytometric quantification of CD80 and CD86 expression on lung and MLN CD103⁺ DCs after PR8 infection. Values are given as mean intensities ×1,000 of PE (CD80) and PE-Cy7 (CD86) fluorescence. Data are mean ± SD. *P < 0.05, **P < 0.01, ***P < 0.005.