InIA- but not InIB-mediated internalization of Listeria monocytogenes by non-phagocytic mammalian cells needs the support of other internalins
InIA- but not InIB-mediated internalization of Listeria monocytogenes by non-phagocytic mammalian cells needs the support of other internalins
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DOI：
10.1046/j.1365-2958.2002.02767.x
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发表时间：
2002-02-01
影响因子：
3.6
通讯作者：
Goebel, W
中科院分区：
文献类型：
--
作者：
Bergmann, B;Raffelsbauer, D;Goebel, W
为了确定先前鉴定的内化蛋白InlA、InlB、InlC、InlE、InlG和InlH对单核细胞增生李斯特菌被非专职吞噬哺乳动物细胞内化的贡献，我们构建了在相应的inl基因中具有各种缺失组合的突变体。研究了这些突变体在上皮样Caco-2和微血管内皮HBMEC细胞系中的内化。inlGHE基因簇或单个基因的缺失导致HBMEC和其他非吞噬哺乳动物细胞的内化增加2至4倍。在没有InlB的情况下，HBMEC的侵袭被完全阻断，并且InlB依赖性内化不需要任何其他内化蛋白的存在。在InlA和InlB不存在的情况下，Caco-2细胞的内化降低至约1%的水平，并且在InlA、InlB和InlC存在的情况下以及在InlG、InlH和InlE不存在的情况下最有效。InlB和InlA，在每种情况下，在不存在其他内化蛋白的情况下，导致（与野生型菌株相比）分别降低约20%和小于10%的内化。InlA依赖性内化（在不存在InlB的情况下）需要InlC和InlGHE的额外功能。inlGHE的缺失增强了InlA和InlB的表达。InlA含量的增加导致L.单核细胞增生症与Caco-2细胞的早期联合，而在缺乏其他internalins的情况下，不增强其摄取，而大量的InlB并不增强L.单核细胞增多症与HBMEC的关系，但导致L.单核细胞增多症。结果表明，InlB能够单独诱导HBMEC和Caco-2细胞中的吞噬作用（效率较低），但InlA需要其他内分泌蛋白的支持功能来触发吞噬作用。这些内分泌蛋白似乎都不是乳酸杆菌细胞间传播所必需的。单核细胞增多症，如通过显微注射具有适当的inl突变体的Caco-2细胞所示。
To determine the contribution of the previously identified internalins, InlA InlB, InlC, InlE, InlG, and InlH, to internalization of Listeria monocytogenes by nonprofessional phagocytic mammalian cells, we constructed mutants with various combinations of deletions in the respective inl genes. Internalization of these mutants into the epithelial-like Caco-2 and the microvascular endothelial HBMEC cell lines were studied. Deletion of the inlGHE gene cluster, or of the single genes, led to a two to fourfold increased internalization by HBMEC and other non-phagocytic mammalian cells. Invasion into HBMEC was totally blocked in the absence of InlB, and InlB-dependent internalization did not require the presence of any of the other internalins. Internalization by Caco-2 cells was reduced to a level of about 1% in the absence of InlA and InlB, and was most efficient in the presence of InlA, InlB and InlC and in the absence of InlG, InlH and InlE. InlB and InlA, in each case in the absence of the other internalins, led (compared with the wildtype strain) to reduced internalization of about 20% and less than 10% respectively. InlA-dependent internalization (in the absence of InlB) required the additional function of InlC and InlGHE. The deletion of inlGHE enhanced the expression of InlA and InlB. The increased amount of InlA led to an increase in early association of L. monocytogenes with Caco-2 cells without enhancing its uptake in the absence of the other internalins, whereas the larger amount of InlB did not enhance early association of L. monocytogenes with HBMEC but led to an increase in internalization of L. monocytogenes. The results suggest that InlB is able to induce phagocytosis in HBMEC and (at a lower efficiency) in Caco-2 cells by itself, but InlA needs the supportive functions of the other internalins to trigger phagocytosis. None of these internalins seems to be required for cell-to-cell spread by L. monocytogenes, as shown by microinjection of Caco-2 cells with appropriate inl mutants.