Pelc R S, McClure J C, Sears K T, Chung A, Rahman M S, Ceraul S M
Department of Microbiology and Immunology, University of Maryland School of Medicine, Baltimore, MD, USA.
Insect Mol Biol. 2014 Aug;23(4):457-65. doi: 10.1111/imb.12094. Epub 2014 Apr 29.
The importance of tick defensins is evidenced by their expression in a wide variety of tick tissues and prevalence across many tick genera. To date, the functional and biological significance of defensin-2 as a rickettsiastatic or rickettsiacidal antimicrobial peptide has not been addressed. In a previous study, defensin-2 transcription was shown to increase in Dermacentor variabilis ticks challenged with Rickettsia montanensis. In the present study, the hypothesis that defensin-2 is functional as a rickettsiastatic and/or rickettsiacidal antimicrobial peptide is tested. We show that defensin-2 plays a role in reducing burden after acquisition of Rickettsia montanensis through capillary feeding. Moreover, defensin-2 is shown to associate with R. montanensis in vitro and in vivo, causing cytoplasmic leakiness.
蜱防御素的重要性体现在它们在多种蜱组织中的表达以及在许多蜱属中的广泛存在。迄今为止，防御素-2作为一种抗立克次氏体或杀立克次氏体抗菌肽的功能和生物学意义尚未得到探讨。在先前的一项研究中，已表明感染蒙大拿立克次氏体的变异革蜱中防御素-2的转录会增加。在本研究中，对防御素-2作为抗立克次氏体和/或杀立克次氏体抗菌肽具有功能这一假设进行了验证。我们发现，通过毛细管喂食感染蒙大拿立克次氏体后，防御素-2在减轻负担方面发挥了作用。此外，在体外和体内实验中均显示防御素-2与蒙大拿立克次氏体相关联，导致细胞质渗漏。
