Figure 4.

Conducting airway epithelial cells produce Sectm1 during pneumonia. (A and B) Surfactant protein (SP) C–green fluorescent protein (GFP) transgenic mice were infected with S. pneumoniae serotype 19F. Left lungs were harvested 24 hours after infection and digested to single-cell suspensions with elastase. Four cell populations consisting of CD45⁺, CD45⁻GFP^bright, CD45⁻GFP⁻EpCAM⁺T1α^bright, and CD45⁻GFP⁻EpCAM⁺T1α⁻ were sorted by flow cytometry. Expression of SPC, caveolin-1, CC10, and Forkhead box protein J1 (Foxj1) were measured across these four cell populations using qRT-PCR. Values represent fold induction relative to CD45⁺ cells and are expressed as means (±SEM). Significance was determined by one-way ANOVA with Sidak’s post hoc test (n = 4 in each group). *P < 0.05 versus CD45⁺. (C) Sectm1 transcripts were measured using qRT-PCR across the four cell populations. Values represent fold induction relative to CD45⁺ cells and are expressed as means (±SEM). Significance was determined by one-way ANOVA with Sidak’s post hoc test (n = 4 in each group). *P < 0.05 versus CD45⁺. EpCAM, epithelial cell adhesion molecule; SSC, side scatter.