Department of Zoology, University of Oxford, Peter Medawar Building for Pathogen Research, Oxford, United Kingdom.
PLoS Pathog. 2010 Oct 7;6(10):e1001143. doi: 10.1371/journal.ppat.1001143.
The over-replicating wMelPop strain of the endosymbiont Wolbachia pipientis has recently been shown to be capable of inducing immune upregulation and inhibition of pathogen transmission in Aedes aegypti mosquitoes. In order to examine whether comparable effects would be seen in the malaria vector Anopheles gambiae, transient somatic infections of wMelPop were created by intrathoracic inoculation. Upregulation of six selected immune genes was observed compared to controls, at least two of which (LRIM1 and TEP1) influence the development of malaria parasites. A stably infected An. gambiae cell line also showed increased expression of malaria-related immune genes. Highly significant reductions in Plasmodium infection intensity were observed in the wMelPop-infected cohort, and using gene knockdown, evidence for the role of TEP1 in this phenotype was obtained. Comparing the levels of upregulation in somatic and stably inherited wMelPop infections in Ae. aegypti revealed that levels of upregulation were lower in the somatic infections than in the stably transinfected line; inhibition of development of Brugia filarial nematodes was nevertheless observed in the somatic wMelPop infected females. Thus we consider that the effects observed in An. gambiae are also likely to be more pronounced if stably inherited wMelPop transinfections can be created, and that somatic infections of Wolbachia provide a useful model for examining effects on pathogen development or dissemination. The data are discussed with respect to the comparative effects on malaria vectorial capacity of life shortening and direct inhibition of Plasmodium development that can be produced by Wolbachia.
共生菌沃尔巴克氏体的过度复制 wMelPop 菌株最近被证明能够诱导埃及伊蚊的免疫上调和病原体传播抑制。为了研究类似的效果是否会在疟疾传播媒介冈比亚按蚊中出现，通过胸腔内接种创建了 wMelPop 的瞬时体感染。与对照组相比，观察到六个选定的免疫基因上调，其中至少有两个（LRIM1 和 TEP1）影响疟疾寄生虫的发育。稳定感染的 An. gambiae 细胞系也显示出与疟疾相关的免疫基因表达增加。在 wMelPop 感染组中观察到疟原虫感染强度的高度显著降低，并且通过基因敲低，获得了 TEP1 在这种表型中的作用的证据。比较 Ae. aegypti 中体和稳定遗传的 wMelPop 感染中的上调水平表明，体感染中的上调水平低于稳定转染系；然而，在体感染的 wMelPop 感染的雌性中观察到对丝虫的发育抑制。因此，我们认为如果能够创建稳定遗传的 wMelPop 转染，在冈比亚按蚊中观察到的效果可能更为明显，并且沃尔巴克氏体的体感染为研究对病原体发育或传播的影响提供了有用的模型。该数据是关于沃尔巴克氏体缩短寿命和直接抑制疟原虫发育对疟疾媒介能力的相对影响进行讨论的。
