Anatriello Elen, Oliveira Carlo José Freire, Oliveira Nathália Baptista, Fisch Andressa, Milanezi Cristiane Maria, da Silva João Santana, de Miranda-Santos Isabel Kinney Ferreira, Ferreira Beatriz Rossetti
Institute of Science and Technology, Federal University of São Paulo, UNIFESP, Rua Talim, 330, São José dos Campos, São Paulo, 12231-280, Brazil.
Institute of Biological and Natural Sciences, Federal University of Triângulo Mineiro, UFTM, Praça Manoel Terra, 330, Uberaba, Minas Gerais, 38015-050, Brazil.
Parasit Vectors. 2017 Jul 10;10(1):326. doi: 10.1186/s13071-017-2248-8.
It has recently been demonstrated that saliva from Rhipicephalus sanguineus ticks contains adenosine (ADO) and prostaglandin E2 (PGE2), two non-protein molecules that have significant immunomodulatory properties. These molecules can inhibit cytokine production by dendritic cells (DCs), while also reducing the expression of CD40 in these cells. However, more studies are needed for a better understanding of their participation in the feeding of ticks in vivo. This work, therefore, evaluated the importance of ADO during tick infestations. Mice were infested with adult ticks (3 couples/mouse), and their skin was collected at the tick-infested site (3rd and 7th day), and mRNA for receptors of ADO was quantified by real-time PCR.
Tick infestation increased by four and two times the expression of the A2b and A3v1 receptors on day 3, respectively, while expression of other ADO receptors was unaltered. In addition, we treated mice (n = 10/group) daily with 8-(p-Sulfophenyl)theophylline, 8-pSPT, 20 mg/kg, i.p.), a non-selective antagonist of ADO receptors, and evaluated the performance of ticks during infestations. Female ticks fed on 8-pSPT-treated mice presented a reduction in their engorgement, weight and hatching rates of egg masses, and survival times of larvae compared to the same parameters presented by ticks in the control group. To investigate if these 8-pSPT-treated mice presented altered immune responses, we performed three tick infestations and collected their lymph node cells to determine the percentages and activation state of DCs and cytokine production by lymphocytes by flow cytometry (Cytometric Bead Array technique, CBA). Our data showed that 8-pSPT-treated mice presented an increase in the percentage of DCs as well as of their stimulatory and co-stimulatory molecules (CD40, CD80 and MHCII). Regarding production of T cell cytokines, we observed a significant increase in the levels of IL-2 and a significant decrease in IL-10, IL-17, TNF-α and IFN-γ cytokines.
These results suggest that ADO produced by ticks helps them feed and reproduce and that this effect may be due to modulation of host DCs and T cells.
最近有研究表明，血红扇头蜱的唾液中含有腺苷（ADO）和前列腺素E2（PGE2），这两种非蛋白质分子具有显著的免疫调节特性。这些分子可抑制树突状细胞（DCs）产生细胞因子，同时还能降低这些细胞中CD40的表达。然而，需要更多的研究来更好地了解它们在蜱虫体内取食过程中的作用。因此，本研究评估了ADO在蜱虫侵染过程中的重要性。将成年蜱虫（3对/只小鼠）侵染小鼠，在侵染部位（第3天和第7天）采集皮肤，通过实时PCR定量ADO受体的mRNA。
在第3天，蜱虫侵染分别使A2b和A3v1受体的表达增加了4倍和2倍，而其他ADO受体的表达未发生改变。此外，我们每天用8-（对-磺基苯基）茶碱（8-pSPT，20 mg/kg，腹腔注射）处理小鼠（每组10只），8-pSPT是一种非选择性ADO受体拮抗剂，并评估蜱虫在侵染过程中的表现。与对照组蜱虫的相同参数相比，取食8-pSPT处理小鼠的雌性蜱虫饱血程度、体重、卵块孵化率和幼虫存活时间均有所降低。为了研究这些8-pSPT处理的小鼠是否呈现出改变的免疫反应，我们进行了三次蜱虫侵染，并收集它们的淋巴结细胞，通过流式细胞术（细胞计数珠阵列技术，CBA）确定DCs的百分比和活化状态以及淋巴细胞产生的细胞因子。我们的数据显示，8-pSPT处理的小鼠DCs及其刺激分子和共刺激分子（CD40、CD80和MHCII）的百分比增加。关于T细胞细胞因子的产生，我们观察到IL-2水平显著升高，而IL-10、IL-17、TNF-α和IFN-γ细胞因子水平显著降低。
这些结果表明，蜱虫产生的ADO有助于它们取食和繁殖，这种作用可能是由于对宿主DCs和T细胞的调节。
