Invasion of vero cells and induction of apoptosis in macrophages by pathogenic Leptospira interrogans are correlated with virulence
Invasion of vero cells and induction of apoptosis in macrophages by pathogenic Leptospira interrogans are correlated with virulence
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DOI：
10.1128/iai.65.2.729-738.1997
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发表时间：
1997-02-01
影响因子：
3.1
通讯作者：
Perolat, P
中科院分区：
文献类型：
--
作者：
Merien, F;Baranton, G;Perolat, P
应用双荧光免疫标记法检测了强毒钩端螺旋体黄疸出血血清型凡尔登株与非洲绿色猴肾成纤维细胞和单核巨噬细胞样细胞系（J774A.1）的相互作用。根据（i）钩端螺旋体与真核细胞之间的接触持续时间和（ii）从致死性感染豚鼠中初步分离后的体外传代次数，研究了抗感染性特征。用相应的高传代无毒力变体和腐殖型钩端螺旋体双曲钩端螺旋体Patoc I进行比较实验。在Vero细胞中，从感染后20分钟起，毒力钩端螺旋体迅速内化，而无毒力和溶血性菌株仍然位于细胞外。此外，强毒株表现出在接触的早期阶段主动侵入单核细胞-巨噬细胞样J774A.1细胞并诱导程序性细胞死亡的能力，如定量夹心酶免疫测定中寡核小体检测所示。在这两种细胞系统中，随后的体外传代培养证明了侵入性的逐步降低，指出了使用钩端螺旋体的毒力研究的原代培养物的必要性。单旦尸胺能显著抑制毒性钩端螺旋体的侵袭性，表明内化依赖于受体介导的内吞作用。钩端螺旋体的致病性可能与其对宿主上皮细胞的侵袭和对巨噬细胞凋亡的诱导有关，二者均有助于其在宿主体内存活和逃避免疫应答。
Interactions of virulent Leptospira interrogans serovar icterohaemorrhagiae strain Verdun with Vero cells (African green monkey kidney fibroblasts) and a monocyte-macrophage-like cell line (J774A.1) were assayed by a double-fluorescence immunolabelling method. Infectivity profiles were investigated according to (i) the duration of contact between leptospires and eukaryotic cells and (ii) the number of in vitro passages after primary isolation from lethally infected guinea pigs. Comparative experiments were conducted with the corresponding high-passage avirulent variant and the saprophytic leptospire Leptospira biflexa Patoc I. In Vero cells, virulent leptospires were quickly internalized from 20 min postinfection, whereas avirulent and saprophytic strains remained extracellularly located. In addition, the virulent strain demonstrated an ability to actively invade the monocyte-macrophage-like J774A.1 cells during the early stages of contact and to induce programmed cell death, as shown by the detection of oligonucleosomes in a quantitative sandwich enzyme immunoassay. In both cellular systems, subsequent in vitro subcultures demonstrated a progressive decrease of the invasiveness, pointing out the necessity of using primocultures of Leptospira for virulence studies. Invasiveness of virulent leptospires was significantly inhibited with monodansylcadaverine, indicating that internalization was dependent on receptor-mediated endocytosis. Invasion of epithelial cells and induction of apoptosis in macrophages may be related to the pathogenicity of Leptospira, and both could contribute to its ability to survive in the host and to escape from the immune response.