Cupp E W, Cupp M S
Department of Entomology, Auburn University, AL 36849-5413, USA.
J Med Entomol. 1997 Mar;34(2):87-94. doi: 10.1093/jmedent/34.2.87.
When blood-feeding, black flies introduce secretions into the feeding lesion that act in a coordinated manner on the 3 arms of the vertebrate hemostatic system (platelet aggregation, coagulation, and vasoconstriction). Apyrase activity inhibits platelet aggregation and is ubiquitous in the saliva of black flies, although activity per gland varies by species and has a positive association with anthropophagy. Anticoagulants target components in the final common pathway of the coagulation cascade, including factors V, Xa, and II (thrombin). The antithrombin salivary protein may exert a redundant effect by inhibiting the role of thrombin in platelet aggregation. Antithrombin presence and activity also varies among black fly species, and exhibits a positive correlation with zoophagy. Vasodilation of capillaries to increase blood supply to the feeding wound appears to be an important requirement for Simulium spp., because substantial erythema-inducing activity, has been demonstrated in salivary glands of all New World species examined. Salivary glands of Simulium ochraceum (Walker), a highly anthropophilic vector of Onchocerca volvulus (Leuckhart), contain greater vasodilator activity than several other species, including S. metallicum Bellardi, a secondary zoophagic vector of human onchocerciasis. Simulium vittatum Zetterstedt saliva affects immune cell responses and cytokine production. The ability of the saliva to modulate components of the host immune system provides an opportunity for enhancing transmission of pathogens during bloodfeeding. Thus, the likely possibility that effective pathogen transmission relies on vector saliva may complement present efforts aimed at target epitopes of O. volvulus or identify additional molecules to be investigated as part of a "river blindness" vaccine cocktail. Components in saliva also may enhance the transmission of other microbial agents either by a cofeeding process similar to that observed in ixodid ticks or through rupture of the labrum during escape of Onchocerca infective stage larvae. In a few instances, saliva of some Simulium spp. also has been associated with extensive tissue and organ pathology, including hemorrhagic shock and death. Pathologic signs associated with this syndrome indicate an enhanced antihemostatic activity in saliva.
在吸血时，蚋会将分泌物注入吸血创口，这些分泌物会以协同方式作用于脊椎动物止血系统的三个环节（血小板聚集、凝血和血管收缩）。腺苷三磷酸双磷酸酶活性可抑制血小板聚集，在蚋的唾液中普遍存在，不过每个腺体的活性因物种而异，且与嗜人血呈正相关。抗凝剂作用于凝血级联反应最终共同途径中的成分，包括因子V、Xa和II（凝血酶）。抗凝血酶唾液蛋白可能通过抑制凝血酶在血小板聚集中的作用发挥冗余效应。抗凝血酶的存在和活性在不同蚋种中也有所不同，且与嗜动物血呈正相关。毛细血管扩张以增加对吸血创口的血液供应似乎是蚋属物种的一个重要需求，因为在所有已检测的新大陆物种的唾液腺中都已证明存在显著的红斑诱导活性。旋盘尾丝虫（Leuckhart）的高度嗜人血传播媒介奥氏蚋（Walker）的唾液腺比其他几个物种具有更强的血管舒张活性，包括人类盘尾丝虫病的次要嗜动物血传播媒介金属蚋（Bellardi）。北美蚋（Zetterstedt）的唾液会影响免疫细胞反应和细胞因子产生。唾液调节宿主免疫系统成分的能力为吸血过程中增强病原体传播提供了机会。因此，有效病原体传播可能依赖于媒介唾液这一可能性，可能会补充目前针对旋盘尾丝虫靶抗原表位的研究工作，或确定作为“河盲症”疫苗组合一部分有待研究的其他分子。唾液中的成分也可能通过类似于在硬蜱中观察到的共食过程，或在盘尾丝虫感染期幼虫逸出时通过上唇破裂，来增强其他微生物病原体的传播。在少数情况下，一些蚋种的唾液还与广泛的组织和器官病理变化有关，包括失血性休克和死亡。与该综合征相关的病理迹象表明唾液中的抗止血活性增强。
