Differences between Mycobacterium-Host Cell Relationships in Latent Tuberculous Infection of Mice Ex Vivo and Mycobacterial Infection of Mouse Cells In Vitro

Figure 5

Representative confocal fluorescent images of macrophages (Mph) stained by the LysoTracker Red DND-99 dye (red signal) and mycobacterial LAM-specific antibodies (green signal) show lack of colocalization of BCG-mycobacteria with host cell lysosomes (lack of yellow signal). Nuclei are stained by DAPI (blue signal). The scale bars are 10 μm each. (a) Fragments of splenic granulomas from mouse 2 on 20 days following BCG infection in vivo. In the right panels, the same fragments as in the other panels restained for acid-fast BCG-mycobacteria by the ZN method. Macrophages containing BCG-mycobacteria are indicated by the white arrows on the fluorescent images (left panels) and the black arrows on the 3D (central panels) and ZN (right panels) images. The red arrow in the lower-right panel indicates a macrophage, which does not contain acid-fast BCG-mycobacteria but has one LAM-labeled BCG-Mycobacterium in it on the fluorescent images (left and central panels). (b) Cells with BCG-mycobacteria in the cultures of mouse bone marrow and peritoneal macrophages following infection with the BCG vaccine in vitro and after culture for several hours. Macrophages and neutrophils with BCG-mycobacteria in them are indicated by the white and red arrows, respectively, on the fluorescent image (upper-left panel) and the black and red arrows, respectively, on the 3D image (upper-right panel). Abbreviations as in Figure 1.

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