Centre for Immunology and Infection, Department of Biology, University of York, Heslington, York YO10 5DD, United Kingdom.
Int J Parasitol. 2011 Nov;41(13-14):1347-59. doi: 10.1016/j.ijpara.2011.08.003. Epub 2011 Oct 5.
The surface tegument of the liver fluke Fasciola hepatica is a syncytial cytoplasmic layer bounded externally by a plasma membrane and covered by a glycocalyx, which constitutes the interface between the parasite and its ruminant host. The tegument's interaction with the immune system during the fluke's protracted migration from the gut lumen through the peritoneal cavity and liver parenchyma to the lumen of the bile duct, plays a key role in the fluke's establishment or elimination. However, little is known about proteins of the tegument surface or its secretions. We applied techniques developed for the blood fluke, Schistosoma mansoni, to enrich a tegument surface membrane preparation and analyse its composition by tandem mass spectrometry using new transcript databases for F. hepatica. We increased the membrane and secretory pathway components of the final preparation to ∼30%, whilst eliminating contaminating proteases. We identified a series of proteins or transcripts shared with the schistosome tegument including annexins, a tetraspanin, carbonic anhydrase and an orthologue of a host protein (CD59) that inhibits complement fixation. Unique to F. hepatica, we also found proteins with lectin, cubulin and von Willebrand factor domains plus 10 proteins with leader sequences or transmembrane helices. Many of these surface proteins are potential vaccine candidates. We were hampered in collecting tegument secretions by the propensity of liver flukes, unlike blood flukes, to vomit their gut contents. We analysed both the 'vomitus' and a second supernatant released from haematin-depleted flukes. We identified many proteases, some novel, as well as a second protein with a von Willebrand factor domain. This study demonstrates that components of the tegumental surface of F. hepatica can be defined using proteomic approaches, but also indicates the need to prevent vomiting if tegument secretions are to be characterised.
肝片形吸虫的体表被膜是一层合胞质的细胞质层,外部由质膜包围,表面覆盖着糖萼,构成了寄生虫与其反刍宿主之间的界面。在肝片形吸虫从肠道腔通过腹膜腔和肝实质向胆管腔的漫长迁移过程中,被膜与免疫系统的相互作用在其定居或消除中起着关键作用。然而,对于被膜表面或其分泌物的蛋白质知之甚少。我们应用针对血吸 Schistosoma mansoni 开发的技术,富集了被膜表面膜制剂,并使用肝片形吸虫的新转录数据库通过串联质谱分析其组成。我们将最终制剂的膜和分泌途径成分增加到约 30%,同时消除了污染的蛋白酶。我们鉴定了一系列与血吸虫被膜共享的蛋白质或转录本,包括 annexins、tetraspanin、碳酸酐酶和宿主蛋白(CD59)的同源物,该蛋白抑制补体固定。肝片形吸虫特有的是,我们还发现了具有凝集素、cubulin 和 von Willebrand 因子结构域的蛋白质,以及 10 种具有前导序列或跨膜螺旋的蛋白质。其中许多表面蛋白是潜在的疫苗候选物。与血吸不同,肝吸容易呕吐肠道内容物,这使得我们在收集被膜分泌物时遇到了困难。我们分析了“呕吐物”和从血红素耗尽的吸虫中释放的第二种上清液。我们鉴定了许多蛋白酶,包括一些新的蛋白酶,以及第二种具有 von Willebrand 因子结构域的蛋白质。这项研究表明,肝片形吸虫被膜表面的成分可以通过蛋白质组学方法来定义,但也表明如果要对被膜分泌物进行特征描述,就需要防止呕吐。
Int J Parasitol. 2011-10-5
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