Expression of ClC-7 in alveolar macrophages: role in the establishment of lysosomal pH. (A) The expression of ClC-7 in membranes isolated from fibroblasts of wild-type (WT) and ClC-7 knockout (KO) mice and in RAW264.7 macrophages was tested by immunoblotting, using the antibody described in Kornak et al. (2001). To verify comparable loading, the blots were also probed for the Golgi protein GM130 and for actin. (B) Alveolar macrophages obtained from wild-type (Clcn7^+/+) and ClC-7 knockout mice (Clcn7^−/−) were immunostained for ClC-7 (middle column; green in right column) and for the macrophage marker F4/80 (red in right column), and their nuclei stained with Hoechst 33342 (blue). Corresponding bright-field images are shown in the left column. Bar, 10 µm. (C) Lysosomal pH in alveolar macrophages harvested from wild-type (black bars) or Clcn7^−/− mice without or with 10 µM CFTR_INH-172 (gray and white bars, respectively). Four experiments were performed per mouse type. For each experiment, at least 10 cells (each with ≥10 lysosomes) were measured.