Alveolar epithelial injury and recovery in SpT4-infected mice.
Lung tissues were collected at 0, 2, 4, 7, and 14 dpi with SpT4. (A) Immunostaining on lung sections with antibodies to the type 4 capsule of SpT4, T1a, and pro-SPC (SPC). Cell apoptosis was measured by TUNEL staining. Cell nuclei were stained with DAPI (blue). Scale bars: 50 μm. (B) Mouse lungs were homogenized, and lung lysates were plated for quantitative culture of colonizing pneumococci. (C) Quantification of cell apoptosis by counting TUNEL+ cells on lung sections. (D) Lung cells were dissociated, and T1a+ cells were quantified as percentage of total CD45– cells by flow cytometry. (E) Quantification of the number of SPC+ cells on lung sections. n ≥ 10 randomly selected fields per animal (C and E); n = 3–9 per group (B–E). **P < 0.01; ***P < 0.001; ****P < 0.0001, 1-way ANOVA.