Immune defense mechanisms against a systemic bacterial infection in the cat flea (Ctenocephalides felis)
Immune defense mechanisms against a systemic bacterial infection in the cat flea (Ctenocephalides felis)
复制标题
猫蚤（Ctenocephalides felis）针对系统性细菌感染的免疫防御机制
DOI：
10.1016/j.jip.2022.107850
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发表时间：
2022
影响因子：
3.4
通讯作者：
Brown, Lisa D.
中科院分区：
文献类型：
--
作者：
Muñoz, Melanie;Lin, Nathan;Lin, Rickie;King, Brannen;Brown, Lisa D.
大量的工作一直致力于了解节肢动物媒介的细胞和体液免疫反应。虽然跳蚤（蚤目）是许多细菌病原体的载体，但很少有研究研究这些昆虫如何保护自己免受感染。在这项研究中，我们研究了猫蚤（Ctenocephalides felis），目前最重要的跳蚤害虫的人类和许多家畜的血腔中的免疫防御机制。使用细菌的模式物种（藤黄微球菌，粘质沙雷氏菌，和大肠杆菌），我们提供了一个全身感染，并测量了以下内容：血淋巴的抗菌活性，由氧化酶为基础的途径诱导产生的自由基水平，循环血细胞的数量，循环血细胞的吞噬活性，和在体内细菌的杀伤效率时，吞噬活性是有限的。我们的研究结果表明，跳蚤血淋巴的抗微生物活性的增加，在某些种类的细菌，然而，全身感染相同的细菌种类并没有影响过氧化氢（H2O2），一种活性中间体的氧气，在同一时间的水平。此外，循环血细胞的数量增加响应E。大肠杆菌感染，并且这些细胞显示出对这种细菌的强吞噬活性。此外，通过注射聚苯乙烯珠限制吞噬作用随后增加跳蚤对E的易感性。然而，与未处理的跳蚤相比，损害细胞免疫应答本身并不增加跳蚤对感染的易感性。总的来说，这项工作产生了显着的洞察跳蚤如何与细菌病原体在他们的血腔相互作用，并表明细胞和体液免疫反应合作，以打击全身性细菌感染。
A significant amount of work has been devoted towards understanding the cellular and humoral immune responses in arthropod vectors. Although fleas (Siphonaptera) are vectors of numerous bacterial pathogens, few studies have examined how these insects defend themselves from infection. In this study, we investigated the immune defense mechanisms in the hemocoel of cat fleas (Ctenocephalides felis), currently the most important flea pest of humans and many domestic animals. Using model species of bacteria (Micrococcus luteus,Serratia marcescens, andEscherichia coli), we delivered a systemic infection and measured the following: antimicrobial activity of hemolymph, levels of free radicals resulting from the induction of oxidase-based pathways, number of circulating hemocytes, phagocytosis activity of circulating hemocytes, andin vivobacteria killing efficiency when phagocytosis activity is limited. Our results show that the antimicrobial activity of flea hemolymph increases in response to certain species of bacteria; yet, a systemic infection with the same bacterial species did not influence levels of hydrogen peroxide (H2O2), a reactive intermediate of oxygen, at the same time. Additionally, the number of circulating hemocytes increases in response toE. coliinfection, and these cells display strong phagocytic activity against this bacterium. Moreover, limiting phagocytosis by injecting polystyrene beads subsequently increases flea susceptibility toE. coliinfection when compared to injury controls; however, impairing the cellular immune response itself did not increase flea susceptibility to infection when compared to untreated fleas. Overall, this work yields significant insight into how fleas interact with bacterial pathogens in their hemocoel, and suggests that cellular and humoral immune responses cooperate to combat systemic bacterial infections.