马海梅+吾拉木·马木提+张峰波+庞盼+赵慧+丁剑冰

[摘要] 目的 分析新疆细粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解该蛋白特性，预测其抗原表位，为进一步研究和选择包虫病免疫学诊断与防治的最佳候选抗原提供理论依据。 方法 利用生物信息学方法推测EgAgB8/3蛋白氨基酸序列及理化性质，用不同的生物信息学软件分析EgAgB8/3蛋白的特性及二级结构，并结合多参数预测其抗原表位。 结果 EgAgB8/3抗原是由75个氨基酸残基组成的多肽，相对分子质量为8.58×103，等电点为8.5；蛋白特性分析显示EgAgB8/3蛋白α螺旋、β折叠、β转角和无规卷曲等二级结构特点，有3个β转角较好区域可作为表位所在参考区段；3种软件多参数综合分析预测，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）区段。 结论 运用生物信息学分析方法预测到EgAgB8/3抗原3个B细胞的优势表位，对进一步研究EgAgB8/3抗原性和研发更有价值的包虫病免疫诊断与防治靶标具有重要意义。

[关键词] 细粒棘球绦虫；EgAgB8/3；生物信息学；表位

[中图分类号] R383.3 [文献标识码] A [文章编号] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

细粒棘球蚴所致囊型包虫病（cystic echinococcosis，CE）是一种严重人畜共患寄生虫病[1]。我国CE流行区主要集中在内蒙古、新疆、青海、西藏、寧夏、四川、甘肃7个省份的牧区，给当地人生命健康、经济发展和社会和谐稳定带来严重影响。寻找特异性强、敏感性高的候选抗原靶标分子是CE诊断和防治的当务之急。细粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性强、敏感性和特异性高的脂蛋白，为国内外研究热点[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5个约为8 kD的亚单位，各亚单位对不同类型包虫病诊断的敏感性和特异性效能有明显差异[6-7]。本课题组前期研究发现，5个亚单位中以EgAgB8/3在细粒棘球绦虫成虫阶段的表达最为显著[8-9]，提示其有望成为开发研制包虫病防治疫苗和诊断试剂最有潜力的后备靶抗原。为进一步探讨EgAgB8/3抗原结构特点，本研究用生物信息学方法预测分析其抗原表位，以期为包虫病诊断防治最佳候选抗原的选择提供一些理论支撑。

[摘要] 目的 分析新疆细粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解该蛋白特性，预测其抗原表位，为进一步研究和选择包虫病免疫学诊断与防治的最佳候选抗原提供理论依据。 方法 利用生物信息学方法推测EgAgB8/3蛋白氨基酸序列及理化性质，用不同的生物信息学软件分析EgAgB8/3蛋白的特性及二级结构，并结合多参数预测其抗原表位。 结果 EgAgB8/3抗原是由75个氨基酸残基组成的多肽，相对分子质量为8.58×103，等电点为8.5；蛋白特性分析显示EgAgB8/3蛋白α螺旋、β折叠、β转角和无规卷曲等二级结构特点，有3个β转角较好区域可作为表位所在参考区段；3种软件多参数综合分析预测，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）区段。 结论 运用生物信息学分析方法预测到EgAgB8/3抗原3个B细胞的优势表位，对进一步研究EgAgB8/3抗原性和研发更有价值的包虫病免疫诊断与防治靶标具有重要意义。

[关键词] 细粒棘球绦虫；EgAgB8/3；生物信息学；表位

[中图分类号] R383.3 [文献标识码] A [文章编号] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

细粒棘球蚴所致囊型包虫病（cystic echinococcosis，CE）是一种严重人畜共患寄生虫病[1]。我国CE流行区主要集中在内蒙古、新疆、青海、西藏、寧夏、四川、甘肃7个省份的牧区，给当地人生命健康、经济发展和社会和谐稳定带来严重影响。寻找特异性强、敏感性高的候选抗原靶标分子是CE诊断和防治的当务之急。细粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性强、敏感性和特异性高的脂蛋白，为国内外研究热点[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5个约为8 kD的亚单位，各亚单位对不同类型包虫病诊断的敏感性和特异性效能有明显差异[6-7]。本课题组前期研究发现，5个亚单位中以EgAgB8/3在细粒棘球绦虫成虫阶段的表达最为显著[8-9]，提示其有望成为开发研制包虫病防治疫苗和诊断试剂最有潜力的后备靶抗原。为进一步探讨EgAgB8/3抗原结构特点，本研究用生物信息学方法预测分析其抗原表位，以期为包虫病诊断防治最佳候选抗原的选择提供一些理论支撑。

[摘要] 目的 分析新疆细粒棘球蚴EgAgB8/3蛋白氨基酸序列，了解该蛋白特性，预测其抗原表位，为进一步研究和选择包虫病免疫学诊断与防治的最佳候选抗原提供理论依据。 方法 利用生物信息学方法推测EgAgB8/3蛋白氨基酸序列及理化性质，用不同的生物信息学软件分析EgAgB8/3蛋白的特性及二级结构，并结合多参数预测其抗原表位。 结果 EgAgB8/3抗原是由75个氨基酸残基组成的多肽，相对分子质量为8.58×103，等电点为8.5；蛋白特性分析显示EgAgB8/3蛋白α螺旋、β折叠、β转角和无规卷曲等二级结构特点，有3个β转角较好区域可作为表位所在参考区段；3种软件多参数综合分析预测，EgAgB8/3蛋白抗原表位集中在1～7（FVVVAHA）、6～19（HADDDDDEVTKTKK）、32～38（FQSDPLG）区段。 结论 运用生物信息学分析方法预测到EgAgB8/3抗原3个B细胞的优势表位，对进一步研究EgAgB8/3抗原性和研发更有价值的包虫病免疫诊断与防治靶标具有重要意义。

[关键词] 细粒棘球绦虫；EgAgB8/3；生物信息学；表位

[中图分类号] R383.3 [文献标识码] A [文章编号] 1673-7210（2017）05（b）-0008-04

[Abstract] Objective To analyze the amino acid sequencing of EgAgB8/3 protein from Echinococcus granulosus in Xinjiang Uygur Autonomous Region， understand the characteristics of this protein， predict the epitope of its antigen， so as to provide theoretical foundation for further studying and selecting the best alternative antigen of immunological diagnosis and prevention of echinococcosis. Methods The amino acid sequencing and physicochemical property of EgAgB8/3 proteins were predicted by bioinformatics method， the characteristics and secondary structure of EgAgB8/3 proteins were analyzed by different bioinformatics software， and its antigenic epitope was predicted combined with multiple parameters. Results EgAgB8/3 antigen was polypeptide composed of 75 amino acid residues， the relative molecular mass was 8.58×103， isoelectric point was 8.5； the analysis of protein characteristics showed the secondary structure characteristics of α-helix， β-sheet， β-turn and random coil of EgAgB8/3 proteins， among which， there were 3 better areas of β-turn that could be as reference segment of epitope； comprehensive analysis of three software and multiple parameters predicted that， the epitope of EgAgB8/3 protein antigen was mainly located in 1-7 （FVVVAHA）， 6-19 （HADDDDDEVTKTKK） and 32-38 （FQSDPLG）. Conclusion The prediction for dominant epitope of three B cell epitopes of EgAgB8/3 protein by bioinformatics method has important significance for further studying the antigenicity of EgAgB8/3 and developing more valuable target for immunological diagnosis and prevention of echinococcosis.

[Key words] Echinococcus granulosus； EgAgB8/3； Bioinformatics； Epitope

细粒棘球蚴所致囊型包虫病（cystic echinococcosis，CE）是一种严重人畜共患寄生虫病[1]。我国CE流行区主要集中在内蒙古、新疆、青海、西藏、寧夏、四川、甘肃7个省份的牧区，给当地人生命健康、经济发展和社会和谐稳定带来严重影响。寻找特异性强、敏感性高的候选抗原靶标分子是CE诊断和防治的当务之急。细粒棘球蚴抗原B（Echinococcus granulosus antigen B，EgAgB）是包囊囊液中含量多、免疫原性强、敏感性和特异性高的脂蛋白，为国内外研究热点[2-5]。EgAgB包括EgAgB8/1、EgAgB8/2、EgAgB8/3、EgAgB8/4、EgAgB8/5等5个约为8 kD的亚单位，各亚单位对不同类型包虫病诊断的敏感性和特异性效能有明显差异[6-7]。本课题组前期研究发现，5个亚单位中以EgAgB8/3在细粒棘球绦虫成虫阶段的表达最为显著[8-9]，提示其有望成为开发研制包虫病防治疫苗和诊断试剂最有潜力的后备靶抗原。为进一步探讨EgAgB8/3抗原结构特点，本研究用生物信息学方法预测分析其抗原表位，以期为包虫病诊断防治最佳候选抗原的选择提供一些理论支撑。

[16] Ahn CS，Han X，Bae YA，et al. Alteration of immunoproteome profile of Echinococcus granulosus hydatid fluid with progression of cystic echinococcosis [J]. Parasit Vectors，2015，8：1-10.

[17] 黄艳新，鲍永利，李玉新，等.抗原表位预测的免疫信息学方法研究进展[J].中国免疫学杂志，2008，24（9）：857-861.

[18] Almeida RA，Luther DA，Patel D，et al. Predicted antigenic regions of Streptococcus uberis adhesion molecule（SUAM）are involved in adherence to and internalization into mammary epithelial cells [J]. Vet Microbiol，2011，148（2-4）：323-328.

[19] Saha S，Raghava GP. Prediction of continuous B-cell epitopes in an antigen using recurrent neural network [J]. Proteins，2006，65（1）：40-48.

[20] EL-Manzalawy Y，Honanvar V. Recent advances in B-cell epitope prediction methods [J]. Immunome Res，2010，6（2）：52-60.

[21] Ruth ES，Ricardo NG，Dania OGA，et al. An overview of bioinformatics tools for epitope prediction：Implications on vaccine development [J]. J Biomed Inform，2015，53：405-414.

（收稿日期：2017-01-05 本文編辑：张瑜杰）