A library of recombinant Babesia microti cell surface and secreted proteins for diagnostics discovery and reverse vaccinology
A library of recombinant Babesia microti cell surface and secreted proteins for diagnostics discovery and reverse vaccinology
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DOI：
10.1016/j.ijpara.2018.10.003
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发表时间：
2019-02-01
影响因子：
4
通讯作者：
Wright, Gavin J.
中科院分区：
文献类型：
--
作者：
Elton, Catherine M.;Rodriguez, Marilis;Wright, Gavin J.
人类巴贝虫病是一种新出现的蜱传寄生虫病和输血传播的感染，主要由顶复门寄生虫，田鼠巴贝虫引起。目前还没有针对B的许可疫苗。microti和开发可靠的血清学筛查测试将有助于确保献血供应的安全。B的最新测序。Microti基因组已经揭示了许多编码蛋白质的新基因，现在可以测试它们作为亚单位疫苗候选物和诊断血清学标记物的适用性。细胞外蛋白被认为是优秀的疫苗候选物和血清学标记物，因为它们直接暴露于宿主体液免疫系统，但表达为可溶性重组蛋白可能具有挑战性。我们最近开发了一种基于哺乳动物表达系统的方法，该方法可以产生大量功能性重组细胞表面和分泌的寄生虫蛋白。在这里，我们用B。microti基因组序列，以确定54个基因，预计编码表面展示和分泌的蛋白质表达的血液阶段，并显示41（76%）表达使用我们的方法在可检测的水平。我们证明，蛋白质含有构象，热不稳定，表位，并使用它们来血清学分析的动力学的体液免疫反应的两个菌株的B。microti在小鼠感染模型。使用经验证的人感染的血清，我们显示出宿主对B的抗体应答一致。小鼠和人类宿主中的microti感染。最后，我们表明，在哺乳动物细胞中表达的BmSA 1可以引发高抗体滴度在接种疫苗的小鼠使用人类相容性佐剂，但这些抗体并不影响体内感染的病理。我们的重组B. microti细胞表面和分泌的抗原构成了一种有价值的资源，可以有助于血清学诊断测试、疫苗的开发，并阐明宿主-寄生虫相互作用的分子基础。(C)2018作者（S）由Elsevier Ltd代表澳大利亚寄生虫学会出版。
Human babesiosis is an emerging tick-borne parasitic disease and blood transfusion-transmitted infection primarily caused by the apicomplexan parasite, Babesia microti. There is no licensed vaccine for B. microti and the development of a reliable serological screening test would contribute to ensuring the safety of the donated blood supply. The recent sequencing of the B. microti genome has revealed many novel genes encoding proteins that can now be tested for their suitability as subunit vaccine candidates and diagnostic serological markers. Extracellular proteins are considered excellent vaccine candidates and serological markers because they are directly exposed to the host humoral immune system, but can be challenging to express as soluble recombinant proteins. We have recently developed an approach based on a mammalian expression system that can produce large panels of functional recombinant cell surface and secreted parasite proteins. Here, we use the B. microti genome sequence to identify 54 genes that are predicted to encode surface-displayed and secreted proteins expressed during the blood stages, and show that 41 (76%) are expressed using our method at detectable levels. We demonstrate that the proteins contain conformational, heat-labile, epitopes and use them to serologically profile the kinetics of the humoral immune responses to two strains of B. microti in a murine infection model. Using sera from validated human infections, we show a concordance in the host antibody responses to B. microti infections in mouse and human hosts. Finally, we show that BmSA1 expressed in mammalian cells can elicit high antibody titres in vaccinated mice using a human-compatible adjuvant but these antibodies did not affect the pathology of infection in vivo. Our library of recombinant B. microti cell surface and secreted antigens constitutes a valuable resource that could contribute to the development of a serological diagnostic test, vaccines, and elucidate the molecular basis of host-parasite interactions. (C) 2018 The Author(s). Published by Elsevier Ltd on behalf of Australian Society for Parasitology.