Fig. 5. Intracellular germlings escape from the A549 phagosome and grow into hyphae in the extracellular medium. A549 cells were incubated with A. fumigatus conidia for 24 (a) or 36 (b) hours. Following infection, samples were processed for immunofluorescence. From left to right: differential interference contrast (DIC) image, fluorescence image showing the green channel (total conidia/hyphae), fluorescence image of the red channel (extracellular conidia), and a merged overlay of all images. Bars, 10 µm. The results are representative of two independent experiments. Note that some conidia/hyphae are seen in the DIC image but not the green channel since the fluorescent image represents a single 0.2 µm section that only detects signals from spores in the same plane.