Figure 1. Localization of CFTR in human neutrophils and phagolysosomes.

a & c, DAPI staining of nuclei of human neutrophils. b, anti-CFTR antibody staining of a human neutrophil revealing a punctate staining pattern. d, isotype-matched antibody staining as a control. e–h, double immunofluorescent staining with rabbit anti-human myeloperoxidase antibody (f) and mouse anti-CFTR antibody (g). The merged image (h) to identify co-localization of CFTR and MPO. i–l, CFTR association with phagocytic vacuoles and phagolysosomes bearing ingested green fluorescence protein-expressing Pseudomonas aeruginosa (GFP-PAO1). DAPI staining of a neutrophil with ingested bacteria (i). Phagocytosed GFP-PAO1 (j). Anti-CFTR immunofluorescent staining of a neutrophil with ingested bacteria (k). Association of internalized GFP-PAO1 bacteria with CFTR (l). Large arrows point to a phagolysosome where CFTR is present on the membrane (j–i). Small arrows point to the CFTR-positive staining granules appearing attached to the phagosomes with ingested GFP-PAO1 (j–i). Arrowheads point to a phagocytic vacuole (j–i). m–p, co-localization of CFTR and lysosomal associated membrane protein-1(LAMP-1) in isolated phagolysosomes. DAPI staining of phagolysosomes with ingested non-fluorescent PAO1 which are stained blue (m). LAMP-1 is localized to the phagolysosomes (n). CFTR is present in the phagolysosomal membranes (o). Merged image shows the co-localization of the two proteins (p).