Lai Xin-He, Golovliov Igor, Sjöstedt Anders
Department of Clinical Microbiology, Clinical Bacteriology, Umeå University, SE-901 85 Umeå, Sweden.
Microb Pathog. 2004 Nov;37(5):225-30. doi: 10.1016/j.micpath.2004.07.002.
Francisella tularensis is a facultative intracellular bacterium capable of inducing apoptosis in murine macrophages. In a previous study, an iglC null mutant of F. tularensis live vaccine strain LVS was generated by allelic replacement and in the current study this iglC mutant was successfully complemented in trans. We characterized the capacity of this iglC mutant and the complemented strain to induce macrophage apoptosis. The iglC mutant did not induce apoptosis in the infected cells. In contrast, the complemented iglC strain was able to multiply in the murine macrophage-like cell line J774A.1 and induced apoptosis similar to that of the wild-type strain. It is the first successful example of complementation in trans of a F. tularensis mutant strain and more importantly this work provides direct evidence that the intracellular growth ability is essential for F. tularensis to induce macrophage apoptosis.
土拉弗朗西斯菌是一种兼性胞内细菌，能够诱导小鼠巨噬细胞凋亡。在先前的一项研究中，通过等位基因替换构建了土拉弗朗西斯菌活疫苗株LVS的iglC基因缺失突变体，在本研究中，该iglC突变体成功地进行了反式互补。我们对该iglC突变体和互补菌株诱导巨噬细胞凋亡的能力进行了表征。iglC突变体在感染细胞中不诱导凋亡。相比之下，互补的iglC菌株能够在小鼠巨噬细胞样细胞系J774A.1中增殖，并诱导与野生型菌株相似的凋亡。这是土拉弗朗西斯菌突变体菌株反式互补的首个成功实例，更重要的是，这项工作提供了直接证据，证明胞内生长能力对于土拉弗朗西斯菌诱导巨噬细胞凋亡至关重要。
