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首页> 外文期刊>Infection and immunity >Fate of Listeria monocytogenes in murine macrophages: evidence for simultaneous killing and survival of intracellular bacteria.
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Fate of Listeria monocytogenes in murine macrophages: evidence for simultaneous killing and survival of intracellular bacteria.

机译：鼠巨噬细胞中单核细胞增多性李斯特菌的命运：同时杀死细胞内细菌并存活的证据。

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The intracellular survival of the ubiquitous pathogen Listeria monocytogenes was studied in primary cultures of bone marrow-derived mouse macrophages. Bacteria were able to grow rapidly in these cells, with an apparent multiplication rate of about 40 min. Electron microscopy demonstrated that intracellular bacterial replication was the consequence of simultaneous intracellular killing and replication of bacteria in the same cells. Within the first hour following phagocytosis, most bacteria were destroyed in the phagosomal compartment to which they were confined. This was due to early transfer of hydrolytic enzymes to phagosomes, undoubtedly via phagosome-lysosome (P-L) fusion, as demonstrated by a quantitative analysis after staining for a lysosomal marker, acid phosphatase. One hour after infection, about 14% of the bacteria were free in the cytoplasm, in which they multiplied and induced actin polymerization and spreading to adjacent macrophages, as in epithelial cells. By using the 3-(2,4-dinitroanilino)-3'-amino-N-methyldipropylamine staining procedure, direct evidence is presented that all phagosomes were acidified immediately after phagocytosis, thus indicating that intraphagosomal bacteria were exposed to an acidic environment that might favor vacuolar lysis by listeriolysin O. Intracellular growth in macrophages, therefore, appears to be the result of a competition between the expression of the hydrolytic activity of these cells following P-L fusion and the capacity of L. monocytogenes to escape from the acidified phagosomal compartment before P-L fusion has occurred. The finding that concomitant intracellular killing and survival of L. monocytogenes occurs in the same macrophages might explain the high immunogenicity observed in vivo with live bacteria, as opposed to killed bacteria.
机译：在骨髓来源的小鼠巨噬细胞的原代培养中研究了普遍存在的病原体单核细胞增生性李斯特菌的细胞内存活。细菌能够在这些细胞中快速生长，表观繁殖速率约为40分钟。电子显微镜证明细胞内细菌复制是细胞在同一细胞中同时杀灭和复制细菌的结果。在吞噬作用后的第一个小时内，大多数细菌在被限制的吞噬室中被破坏。这是由于水解酶过早地转移至吞噬体，这无疑是通过吞噬体-溶酶体（P-L）融合，如溶酶体标记酸性磷酸酶染色后的定量分析所证实的。感染后一小时，大约14％的细菌在细胞质中游离，它们在其中繁殖并诱导肌动蛋白聚合，并扩散到邻近的巨噬细胞，就像在上皮细胞中一样。通过使用3-（2,4-二硝基苯胺基）-3'-氨基-N-甲基二丙胺染色方法，直接证据显示吞噬作用后所有吞噬体均立即被酸化，因此表明吞噬体细菌暴露于酸性环境中，有利于利斯特菌溶血素O的液泡裂解。因此，巨噬细胞内的细胞内生长似乎是在PL融合后这些细胞的水解活性表达与单核细胞增生李斯特菌从酸化吞噬区室逃逸的能力之间竞争的结果PL融合已经发生。单核细胞增生李斯特氏菌伴随细胞内杀伤和存活发生在同一巨噬细胞中的发现可能解释了活细菌在体内观察到的高免疫原性，与被杀死细菌相反。

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