共 74 条
Legionella pneumophila replication vacuoles mature into acidic, endocytic organelles
被引:183
作者:
Sturgill-Koszycki, S
[1
]
Swanson, MS
[1
]
机构:
[1] Univ Michigan, Dept Immunol & Microbiol, Ann Arbor, MI 48109 USA
关键词:
pathogenesis;
autophagy;
phagosomes;
lysosomes;
macrophages;
D O I:
10.1084/jem.192.9.1261
中图分类号:
R392 [医学免疫学];
Q939.91 [免疫学];
学科分类号:
100102 ;
摘要:
After ingestion by macrophages, Legionella pneumophila inhibits acidification and maturation of its phagosome. After a 6-10-h lag period, the bacteria replicate for 10-14 h until macrophage lysis releases dozens of progeny. To examine whether the growth phase of intracellular L. pneumophila determines the late of its phagosome, interactions between the endosomal network and pathogen vacuoles were analyzed throughout the primary infection period. Surprisingly, as L. pneumophila replicated exponentially, a significant proportion of the vacuoles acquired lysosomal characteristics. By 18 h, 70% contained lysosomal-associated membrane protein 1 (LAMP-1) and 40% contained cathepsin D; 50% of the vacuoles could be labeled by endocytosis, and the pH of this population of vacuoles averaged 5.6. Moreover, L. pneumophila appeared to survive and replicate within lysosomal compartments: vacuoles harboring more than five bacteria also contained LAMP-1, inhibition of vacuole acidification and maturation by bafilomycin A1 inhibited bacterial replication, bacteria within endosomal vacuoles responded to a metabolic inducer by expressing a gfp reporter gene, and replicating bacteria obtained from macrophages, but not broth, were acid resistant. Understanding how L. pneumophila first evades and then exploits the endosomal pathway to replicate within macrophages may reveal the mechanisms governing phagosome maturation, a process also manipulated by Mycobacteria, Leishmania, and Coxiella.
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页码:1261 / 1272
页数:12
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