Fig. 3. Sub-cellular localization of pro-IL-1. (A) Wide-field fluorescence images of LPS-treated (1 µg/ml, 2 hours) murine macrophages treated with digitonin for the indicated time seconds in (sec) after which they were immunostained for IL-1 (green) and cathepsin D (CD, red). Bar, 10 µm. (B) Immunoblot of the supernatants isolated from the experiment described in A for IL-1 (i) and cathepsin D (ii). The corresponding supernatants were also assayed for activity of the cytosolic LDH protein (iii). Images and blots are representative of three independent experiments.