Figure 2.

Identification of cell types expressing caspase-1 in normal mouse lung. (a) Representative immunofluorescence image of a normal lung section showing total caspase-1 localized to bronchiolar epithelium as the most distinct site, as well as cells scattered among alveoli (b). (c) and (d) Corresponding images of (a) and (b) following restaining with H&E. Caspase-1 positive cells included alveolar macrophages (D1) or type II alveolar cells, typically found at the alveolar interseptal junctions and containing vacuole-like lamellar bodies in the cytoplasm (D2, D3). (e) Dual labelling of a lung section for the macrophage marker F4/80 (red) and total caspase-1 (green), revealing colocalization (yellow) in macrophages (inset). (f) Dual labelling of a lung section for surfactant protein D (SPD, red) and caspase-1 (green), revealing colocalization in type II alveolar cells (inset). Scale bars are in microns.