Fig. 5

In vivo detection of E-cad and NE. a, Lung tissue sections from saline control mice were immunostained for mouse E-cad. Under physiologic conditions, E-cad is restricted to epithelial lining (arrowheads), consistent with the known localization of E-cad expression. b, Representative mouse lung tissue section following O.N. challenge with P. aeruginosa. b, upper panels, Immunostaining for E-cad detected the antigen within inflamed airspaces and in close spatial contact with the cellular infiltrates (arrows). b, lower panels, absence of E-cad staining in the presence of preimmune serum. c, absence of staining was seen when the primary antibody was replaced with the preimmune serum. c, Enzymatic activity assay detected free active NE in cell-free BAL. Consistent with the neutrophilic response to P. aeruginosa, increasing levels of active NE were detected in cell-free BAL fluids following O.N. infection (infected tissues). No NE activity was detected in mice challenged with sterile saline (PBS). Purified active NE (100 ng) was used as control. Data were consistent in all challenged mice (bars ± SEM; *** and **** correspond to p < 0.001 and p < 0.000 respectively for infection versus PBS). O.N. corresponds to 24 h. Scale bar of left images, 150 μm. Scale bar of right images, 45 μm