Figure 4

Confocal microscopy of fluorescently-labeled beads or bacteria by MDM and effect of cytochalasin D. Panels A-C: MDM were derived from a patient with non-severe asthma and exposed to either fluorescently-labelled beads (Panel A) or S. aureus for 4 h (green) (Panel B). Panel C shows lack of phagocytosis of S.aureus in the presence of cytochalasin D. Cell cytoplasm was stained with Cell Tracker Red and the nuclei with DAPI (blue). Panels D-F: MDMs were derived from normal subjects (●), non-severe asthmatics (NSA; ■) or severe asthmatics (SA; ▲) and pretreated with cytochalasin D (cyto D; 5 μg/ml) prior to incubation with beads (Panel D), H. i influenzae (Panel E) or S. aureus (Panel F) for 4 h. Phagocytosis was measured by fluorimetry and reported as relative fluorescence units (RFU). NS = not stimulated. A paired t-test was used to determine the effect of Cytochalasin D on phagocytosis. **p < 0.01, ***p < 0.001.