(A) Tracings in different colors show Ca²⁺ responses in different sessile AMs following sequential hyperinflation challenges as shown (solid arrows). Alveolar microinfusions of buffer alone (green tracing), or buffer containing xestospongin C (XeC) (red tracing) were given as shown (dashed arrow) in different lungs. Bars show the group data following the second hyperinflation. Findings were replicated in 10 AMs from 4 lungs. (B) Confocal images show uptake of fluorescent surfactant (FM1-43–labeled) in AMs 2 hours after intranasal instillation. Dotted lines trace alveolar perimeters. Bars show quantification of uptake in lungs. FS, fluorescent surfactant. (C) Bars show flow cytometry quantification of liposome uptake in AMs (CD11C⁺SiglecF⁺), dendritic cells (CD11C⁺SiglecF^–), and alveolar epithelium (EpCam⁺) from lung cell suspension 2 hours after instillation. The liposomes contained rhodamine B–labeled dextran of molecular weight 70 kDa (LIP-FD). The gating strategy is shown in Supplemental Figure 3A and Supplemental Figure 9. n = 3 lungs each group. (D) Confocal images show AM (SiglecF⁺) uptake of LIP-FD 2 hours after intranasal instillation in presence (+, upper panel) or absence of surfactant (–, lower panel). Note, merge images show LIP-FD uptake in macrophages in the presence (upper right) but not absence (lower left) of surfactant. (E) Tracings show Ca²⁺ response in AMs of mice intranasally instilled with liposomes encapsulating PBS (LIP-PBS) or xestospongin C (LIP-XeC) 2 hours prior to lung imaging. Bars show quantification of the percentage of AMs responding with Ca²⁺ increase after hyperinflation in AMs of mice intranasally instilled with LIP-PBS or LIP-XeC 2 hours prior to lung imaging. Data analyses. Group data are mean ± SEM. P values were calculated by 1-way ANOVA with Bonferroni’s correction (C) or paired (A) or unpaired (B and E) t test.