Laboratory of Medical Entomology, Institute René Rachou, Foundation Oswaldo Cruz, Fiocruz-MG, Belo Horizonte, Brazil.
Department of Parasitology, Charles University, Prague, Czech Republic.
Parasit Vectors. 2020 Sep 3;13(1):441. doi: 10.1186/s13071-020-04311-y.
Sand flies are vectors of Leishmania spp., the causative agents of leishmaniasis in vertebrates, including man. The sand fly saliva contains powerful pharmacologically active substances that prevent hemostasis and enhance Leishmania spp. infections. On the other hand, salivary proteins can protect vaccinated mice challenged with parasites. Therefore, sand fly salivary proteins are relevant for the epidemiology of leishmaniasis and can be a potential target for a vaccine against leishmaniasis. Despite this, studies on sand fly salivary glands (SGs) are limited.
The present study analyzes, in detail, the morphology, anatomy and ultrastructure of the SGs of sand fly vectors of the genera Lutzomyia and Phlebotomus. We used histology, transmission and scanning electron microscopy and lectin labeling associated with confocal laser microscopy.
The SGs have conserved and distinct morphological aspects according to the distinct sand fly species. Each SG has a single rounded lobe constituting of c.100-120 secretory cells. The SG secretory cells, according to their ultrastructure and lectin binding, were classified into five different subpopulations, which may differ in secretory pathways.
To the best of our knowledge, these morphological details of sand fly salivary glands are described for the first time. Further studies are necessary to better understand the role of these different cell types and better relate them with the production and secretion of the saliva substances, which has a fundamental role in the interaction of the sand fly vectors with Leishmania.
沙蝇是利什曼原虫（导致脊椎动物包括人类感染利什曼病的病原体）的载体。沙蝇唾液中含有强大的药理学活性物质，可防止止血并增强利什曼原虫感染。另一方面，唾液蛋白可以保护接种寄生虫的实验鼠。因此，沙蝇唾液蛋白与利什曼病的流行病学有关，并且可以作为利什曼病疫苗的潜在靶标。尽管如此，对沙蝇唾液腺（SGs）的研究仍很有限。
本研究详细分析了利什曼属和白蛉属沙蝇载体的 SGs 的形态、解剖结构和超微结构。我们使用了组织学、透射电子显微镜和扫描电子显微镜以及与共聚焦激光显微镜相关的凝集素标记。
根据不同的沙蝇种类，SGs 具有保守和独特的形态特征。每个 SG 都有一个单个的圆形叶，由约 100-120 个分泌细胞组成。根据其超微结构和凝集素结合，SG 分泌细胞可分为五个不同的亚群，它们在分泌途径上可能有所不同。
据我们所知，这些沙蝇唾液腺的形态细节是首次描述的。需要进一步的研究来更好地理解这些不同细胞类型的作用，并更好地将它们与唾液物质的产生和分泌联系起来，这对于沙蝇与利什曼原虫的相互作用具有根本作用。
