Figure 5.

Only viable mycobacterial strains of the tuberculosis complex, as well as listeriolysin O expressing L. monocytogenes strains, efficiently access the cytoplasm. Macrophages infected with killed BCG-GFP and microinjected with 3 kDa revealed no appreciable colocalization of the two signals, and neither did macrophages infected with live SMEG-GFP injected with 3- or 40-kDa-sized tagged dextrans. Intracytoplasmic microinjection of 3-kDa tagged dextrans in macrophages infected with LLO-GFP similarly demonstrate negligible colocalization, indicating bacterial residence within a membrane-impermeable vesicle. Injection of 2,000-kDa Texas Red-tagged dextrans in LLO+GFP revealed substantial signal colocalization (50%), indicating free access of the bacteria to cytoplamically located macromolecules.