FIG. 3.

Disruption of the phagosome and migration of host cell cytoplasmic contents to the phagosome (A) and presence of lysosomal contents in the disrupted LCP in macrophages at 18 h (B). Representative electron micrographs of L. pneumophila-infected macrophages at 18 h postinfection are shown. L. pneumophila (Lpn) bacteria are within disrupted phagosomes (thick black arrows). The intact portions of the membrane are indicated by thin black arrows. White arrows indicate the presence of lysosomal acid phosphatase. In panel A the bacteria surrounded by few vesicles are cytoplasmic whereas in panel B the LCP is disrupted. Note the perinuclear condensation of the chromatin. Abbreviations: A, amorphous material; M, mitochondria; V, vesicles; N, nucleus.