Alvarez Rojas Cristian A, Gauci Charles G, Nolan Matthew J, Harandi Majid Fasihi, Lightowlers Marshall W
The University of Melbourne, Werribee, Victoria 3030, Australia.
Mol Biochem Parasitol. 2012 Jun;183(2):115-21. doi: 10.1016/j.molbiopara.2012.02.005. Epub 2012 Feb 18.
Cystic echinococcosis in humans and livestock animals is caused by infection with the cestode parasite Echinococcus granulosus. A number of genotypes of the parasite (designated G1-G10) are known to exist, with the genotype cluster G1-G3 and genotype G6 being responsible for the majority of humans infections. A recombinant vaccine has been developed for use in livestock to prevent infection with E. granulosus. The vaccine is based on the antigen EG95 which is expressed in the early larval stage (oncosphere) of the parasite. The EG95 antigen was originally cloned from the G1 genotype of E. granulosus and the protein has been found to be encoded by members of a small family of related genes in this genotype. Reliable information has not been available about the likely efficacy of the EG95 vaccine against genotypes other than G1. In this study, genomic DNA cloning techniques were used to characterize seven eg95-related gene fragments from the G6 genotype of E. granulosus. Three proteins appear to be encoded by these genes. Considerable differences were found between the EG95 related proteins from the G6 genotype compared with the EG95 protein from the G1 genotype. These differences suggest that the EG95-related proteins from the G6 genotype may have different antigenic epitopes compared with the current vaccine antigen. Data presented in this study have implications for future vaccine design and provide the information that would enable a G6 genotype-specific vaccine to be developed against E. granulosus, should this be considered a desirable addition to the available tools for control of cystic echinococcosis transmission.
人和家畜的囊型包虫病是由绦虫寄生虫细粒棘球绦虫感染引起的。已知该寄生虫存在多种基因型（命名为G1 - G10），其中G1 - G3基因型簇和G6基因型导致了大多数人类感染。已开发出一种用于家畜的重组疫苗，以预防细粒棘球绦虫感染。该疫苗基于寄生虫幼虫早期阶段（六钩蚴）表达的抗原EG95。EG95抗原最初是从细粒棘球绦虫的G1基因型中克隆出来的，并且已发现该蛋白由该基因型中一个相关基因的小家族成员编码。关于EG95疫苗对G1以外基因型的可能疗效，尚无可靠信息。在本研究中，使用基因组DNA克隆技术对细粒棘球绦虫G6基因型的七个eg95相关基因片段进行了表征。这些基因似乎编码三种蛋白质。与G1基因型的EG95蛋白相比，发现G6基因型的EG95相关蛋白之间存在相当大的差异。这些差异表明，与当前疫苗抗原相比，G6基因型的EG95相关蛋白可能具有不同的抗原表位。本研究中提供的数据对未来疫苗设计具有启示意义，并提供了相关信息，使得在认为针对细粒棘球绦虫开发G6基因型特异性疫苗是控制囊型包虫病传播现有工具的理想补充时能够实现这一目标。
