MglA and igl proteins contribute to the modulation of Francisella tularensis live vaccine strain-containing phagosomes in murine macrophages
MglA and igl proteins contribute to the modulation of Francisella tularensis live vaccine strain-containing phagosomes in murine macrophages
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DOI：
10.1128/iai.00226-08
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发表时间：
2008-08-01
影响因子：
3.1
通讯作者：
Sjostedt, Anders
中科院分区：
文献类型：
--
作者：
Bonquist, Linda;Lindgren, Helena;Sjostedt, Anders
土拉弗朗西斯菌活疫苗株 (LVS) 与其 iglC 突变体相反，在巨噬细胞的细胞质中复制。我们研究了用 LVS 和 iglC、iglD 和 mgl4 突变体感染小鼠巨噬细胞样细胞系 J774A.1 的结果，后者缺乏全局调节因子。与LVS相比，所有突变体在长达72小时内均表现出细胞内复制受损，并且mgl4突变体细菌的数量甚至减少。与 LVS 相比，所有突变体与 LAMP-1 的共定位显着增加，表明逃入细胞质的能力受损。溶酶体酸度依赖性染料在约 40% 的含有突变细菌的液泡中积累，但在含有 LVS 的液泡中则完全不积累。用γ干扰素预激活巨噬细胞抑制了所有菌株的细胞内生长，并显着增加了含有突变体的吞噬体的酸化，但仅略微增加了LAMP-1共定位。 iglC和iglD突变体的细胞内复制和吞噬体逃逸通过反式互补得以恢复。总之，IglC、IglD 和 MglA 蛋白各自直接或间接地对土拉弗拉菌 LVS 的毒力有重要贡献，包括其细胞内复制、细胞质逃逸和吞噬体酸化的抑制。
The Francisella tularensis live vaccine strain (LVS), in contrast to its iglC mutant, replicates in the cytoplasm of macrophages. We studied the outcome of infection of the murine macrophagelike cell line J774A.1 with LVS and with iglC, iglD, and mgl4 mutants, the latter of which is deficient in a global regulator. Compared to LVS, all of the mutants showed impaired intracellular replication up to 72 h, and the number of the mgl4 mutant bacteria even decreased. Colocalization with LAMP-1 was significantly increased for all mutants compared to LVS, indicating an impaired ability to escape into the cytoplasm. A lysosomal acidity-dependent dye accumulated in approximately 40% of the vacuoles containing mutant bacteria but not at all in vacuoles containing LVS. Preactivation of the macrophages with gamma interferon inhibited the intracellular growth of all strains and significantly increased acidification of phagosomes containing the mutants, but it only slightly increased the LAMP-1 colocalization. The intracellular replication and phagosomal escape of the iglC and iglD mutants were restored by complementation in trans. In conclusion, the IglC, IglD, and MglA proteins each directly or indirectly critically contribute to the virulence of F. tularensis LVS, including its intracellular replication, cytoplasmic escape, and inhibition of acidification of the phagosomes.