Kazimírová Mária, Thangamani Saravanan, Bartíková Pavlína, Hermance Meghan, Holíková Viera, Štibrániová Iveta, Nuttall Patricia A
Department of Medical Zoology, Institute of Zoology, Slovak Academy of SciencesBratislava, Slovakia.
Department of Pathology, University of Texas Medical BranchGalveston, TX, United States.
Front Cell Infect Microbiol. 2017 Jul 26;7:339. doi: 10.3389/fcimb.2017.00339. eCollection 2017.
Ticks are efficient vectors of arboviruses, although less than 10% of tick species are known to be virus vectors. Most tick-borne viruses (TBV) are RNA viruses some of which cause serious diseases in humans and animals world-wide. Several TBV impacting human or domesticated animal health have been found to emerge or re-emerge recently. In order to survive in nature, TBV must infect and replicate in both vertebrate and tick cells, representing very different physiological environments. Information on molecular mechanisms that allow TBV to switch between infecting and replicating in tick and vertebrate cells is scarce. In general, ticks succeed in completing their blood meal thanks to a plethora of biologically active molecules in their saliva that counteract and modulate different arms of the host defense responses (haemostasis, inflammation, innate and acquired immunity, and wound healing). The transmission of TBV occurs primarily during tick feeding and is a complex process, known to be promoted by tick saliva constituents. However, the underlying molecular mechanisms of TBV transmission are poorly understood. Immunomodulatory properties of tick saliva helping overcome the first line of defense to injury and early interactions at the tick-host skin interface appear to be essential in successful TBV transmission and infection of susceptible vertebrate hosts. The local host skin site of tick attachment, modulated by tick saliva, is an important focus of virus replication. Immunomodulation of the tick attachment site also promotes co-feeding transmission of viruses from infected to non-infected ticks in the absence of host viraemia (non-viraemic transmission). Future research should be aimed at identification of the key tick salivary molecules promoting virus transmission, and a molecular description of tick-host-virus interactions and of tick-mediated skin immunomodulation. Such insights will enable the rationale design of anti-tick vaccines that protect against disease caused by tick-borne viruses.
蜱是虫媒病毒的高效传播媒介，尽管已知只有不到10%的蜱种是病毒传播媒介。大多数蜱传病毒（TBV）是RNA病毒，其中一些在全球范围内会导致人类和动物患上严重疾病。最近发现，几种影响人类或家养动物健康的TBV已经出现或再次出现。为了在自然界中生存，TBV必须在脊椎动物和蜱细胞中感染并复制，而这两种细胞代表着截然不同的生理环境。关于TBV在蜱细胞和脊椎动物细胞之间切换感染和复制的分子机制的信息很少。一般来说，蜱能够成功完成血餐摄取，得益于其唾液中大量的生物活性分子，这些分子能够对抗和调节宿主防御反应的不同环节（止血、炎症、先天免疫和获得性免疫以及伤口愈合）。TBV的传播主要发生在蜱进食期间，是一个复杂的过程，已知会受到蜱唾液成分的促进。然而，TBV传播的潜在分子机制尚不清楚。蜱唾液的免疫调节特性有助于克服对损伤的第一道防线以及在蜱 - 宿主皮肤界面的早期相互作用，这似乎是TBV成功传播并感染易感脊椎动物宿主的关键。由蜱唾液调节的蜱附着的局部宿主皮肤部位是病毒复制的重要场所。在没有宿主病毒血症的情况下（非病毒血症传播），蜱附着部位的免疫调节也促进了病毒从受感染蜱向未受感染蜱的共进食传播。未来的研究应致力于确定促进病毒传播的关键蜱唾液分子，并对蜱 - 宿主 - 病毒相互作用以及蜱介导的皮肤免疫调节进行分子描述。这些见解将有助于合理设计抗蜱疫苗，以预防蜱传病毒引起的疾病。
