Zuck Meghan, Sherrid Ashley, Suchland Robert, Ellis Tisha, Hybiske Kevin
Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA Program in Infectious Diseases, School of Public Health, University of California, Berkeley, Berkeley, CA, USA.
Division of Allergy and Infectious Diseases, Department of Medicine, University of Washington, Seattle, WA, USA.
Pathog Dis. 2016 Oct;74(7). doi: 10.1093/femspd/ftw093. Epub 2016 Sep 11.
Chlamydiae exit via membrane-encased extrusion or through lysis of the host cell. Extrusions are novel, pathogen-containing structures that confer infectious advantages to Chlamydia, and are hypothesized to promote cell-to-cell spread, dissemination to distant tissues and facilitate immune evasion. The extrusion phenomenon has been characterized for several Chlamydia trachomatis serovars, but a thorough investigation of extrusion for additional clinically relevant C. trachomatis strains and Chlamydia species has yet to be performed. The key parameters investigated in this study were: (i) the conservation of extrusion across the Chlamydia genus, (ii) the functional requirement for candidate Chlamydia genes in extrusion formation i.e. IncA and CT228 and (iii) extrusion-mediated uptake, and consequent survival of Chlamydia inside macrophages. Inclusion morphology was characterized by live fluorescence microscopy, using an inverted GFP strategy, at early and mid-stages of infection. Enriched extrusions were used to infect bone marrow-derived macrophages, and bacterial viability was measured following macrophage engulfment. Our results demonstrate that extrusion is highly conserved across chlamydiae, including ocular, STD and LGV biovars and divergent Chlamydia species. Consequently, this exit mechanism for Chlamydia may fulfill common advantages important for pathogenesis.
衣原体通过膜包裹的挤压或宿主细胞裂解而排出。挤压物是含有病原体的新型结构，赋予衣原体感染优势，据推测可促进细胞间传播、扩散至远处组织并有助于免疫逃避。挤压现象已在几种沙眼衣原体血清型中得到表征，但尚未对其他临床相关的沙眼衣原体菌株和衣原体物种的挤压现象进行全面研究。本研究中调查的关键参数包括：（i）衣原体属中挤压现象的保守性，（ii）挤压形成过程中候选衣原体基因（即IncA和CT228）的功能需求，以及（iii）挤压介导的摄取以及衣原体在巨噬细胞内的存活情况。在感染的早期和中期，使用反向绿色荧光蛋白策略，通过活细胞荧光显微镜对包涵体形态进行表征。用富集的挤压物感染骨髓来源的巨噬细胞，并在巨噬细胞吞噬后测量细菌活力。我们的结果表明，挤压现象在衣原体中高度保守，包括眼部、性传播疾病和淋巴肉芽肿生物变种以及不同的衣原体物种。因此，衣原体的这种排出机制可能具有对发病机制很重要的共同优势。
