Segal G, Shuman H A
Department of Microbiology, College of Physicians & Surgeons, Columbia University, New York, New York 10032, USA.
Infect Immun. 1999 May;67(5):2117-24. doi: 10.1128/IAI.67.5.2117-2124.1999.
In previous reports we described a 22-kb Legionella pneumophila chromosomal locus containing 18 genes. Thirteen of these genes (icmT, -R, -Q, -P, -O, -M, -L, -K, -E, -C, -D, -J, and -B) were found to be completely required for intracellular growth and killing of human macrophages. Three genes (icmS, -G, and -F) were found to be partially required, and two genes (lphA and tphA) were found to be dispensable for intracellular growth and killing of human macrophages. Here, we analyzed the requirement of these genes for intracellular growth in the protozoan host Acanthamoeba castellanii, a well-established important environmental host of L. pneumophila. We found that all the genes that are completely required for intracellular growth in human macrophages are also completely required for intracellular growth in A. castellanii. However, the genes that are partially required for intracellular growth in human macrophages are completely required for intracellular growth in A. castellanii. In addition, the lphA gene, which was shown to be dispensable for intracellular growth in human macrophages, is partially required for intracellular growth in A. castellanii. Our results indicate that L. pneumophila utilizes the same genes to grow intracellularly in both human macrophages and amoebae.
在之前的报告中，我们描述了嗜肺军团菌一个22千碱基对的染色体位点，其中包含18个基因。已发现其中13个基因（icmT、-R、-Q、-P、-O、-M、-L、-K、-E、-C、-D、-J和-B）对于在人类巨噬细胞内生长和杀伤巨噬细胞是完全必需的。发现3个基因（icmS、-G和-F）是部分必需的，2个基因（lphA和tphA）对于在人类巨噬细胞内生长和杀伤巨噬细胞是可有可无的。在此，我们分析了这些基因对于在原生动物宿主卡氏棘阿米巴中细胞内生长的需求，卡氏棘阿米巴是嗜肺军团菌一个公认的重要环境宿主。我们发现，所有对于在人类巨噬细胞内生长完全必需的基因对于在卡氏棘阿米巴内生长也是完全必需的。然而，对于在人类巨噬细胞内生长部分必需的基因对于在卡氏棘阿米巴内生长是完全必需的。此外，已证明对于在人类巨噬细胞内生长可有可无的lphA基因对于在卡氏棘阿米巴内生长是部分必需的。我们的结果表明，嗜肺军团菌利用相同的基因在人类巨噬细胞和变形虫内进行细胞内生长。
