Mechanism of Vector Saliva Inhibition of Innate Immunity

描述（由申请人提供）：蜱的唾液含有许多免疫调节成分，以帮助蜱进食，是病原体的有效载体，包括生物防御C类病原体蜱传脑炎病毒和莱姆病病原体伯氏疏螺旋体（Bb）。在本提案中，我们将验证我们的假设，即蜱虫唾液中的崩解素抑制多态核白细胞（PMN）功能，从而为媒介传播的病原体提供生存优势。我们的计划源于我们之前的工作，我们已经证明唾液抑制PMN粘附并通过减少整合素表达降低病原体杀灭效率。我们将利用RNA干扰的新技术抑制蜱唾液腺中崩解素的表达，以及重组崩解素的表达，以评估抑制PMN功能的分子机制。我们将量化崩解素对PMN激活标记物、炎症介质的产生和体外信号通路的影响。此外，我们将利用莱姆病小鼠模型探讨崩解素对皮肤PMN功能的作用。这项工作的更大意义在于确定了唾液抑制PMN的机制，可以通过治疗干预来提高宿主对媒介传播病原体的免疫力，包括生物防御关注的病原体。

DESCRIPTION (provided by applicant): Saliva of the Ixodes ticks contains numerous immunomodulatory components to aid tick feeding and is a potent delivery vehicle for pathogens, including Biodefense Category C agent tick-borne encephalitis virus and the Lyme disease agent, Borrelia burgdorferi (Bb). In this proposal, we will test our hypothesis that disintegrins from tick saliva inhibit polymorphonuclear leukocyte (PMN) function and thereby provide a survival advantage to vector-borne pathogens. Our plan stems from our previous work, in which we have shown that saliva inhibits PMN adherence and reduces efficiency of pathogen killing through reduction in integrin expression. We will use the novel technology of RNA interference to inhibit the expression of disintegrins in tick salivary glands, as well as recombinant disintegrins, to assess the molecular mechanisms of inhibition of PMN function. We will quantify the effect of disintegrins on markers of PMN activation, production of inflammatory mediators, and signaling pathways in vitro. In addition, we will address the role of disintegrins on PMN function in the skin using the murine model of Lyme disease. The greater significance of this work is the identification of a mechanism of saliva's inhibition of PMN that can be exploited by therapeutic interventions to improve host immunity against vector-borne pathogens, including those of Biodefense concern.