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

Figure 3

Dead (apoptotically or necrotically) and live macrophages containing an increased number of BCG-mycobacteria. Acid-fast BCG-mycobacteria stained by the ZN method. The scale bars are 10 μm each. ((a)-(b)) Cells with the largest number of BCG-mycobacteria and morphological evidence of death in the cultures of mouse (a) bone marrow and (b) peritoneal macrophages following infection with the BCG vaccine in vitro and after culture for several hours. Apoptotic bodies and pieces of the macrophage cytoplasm with or without acid-fast BCG in them are indicated by the black arrows. Cells containing the largest number of BCG-mycobacteria and no nuclei are indicated by the red arrows. Nonacid-fast BCG-mycobacteria (blue color) expelled by macrophages into the extracellular space are indicated by the black snowflakes. (c) Macrophages with the largest number of BCG-mycobacteria in them and without morphological evidence of death are indicated by the black arrows in the fragments of mouse splenic granulomas. The red arrow indicates a dendritic cell with BCG-mycobacteria in it; the green arrow indicates a megakaryocyte. Abbreviations as in Figure 1.

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