Surface expression of an immunodominant malaria protein B cell epitope by yellow fever virus
Surface expression of an immunodominant malaria protein B cell epitope by yellow fever virus
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DOI：
10.1006/jmbi.2001.5258
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发表时间：
2002-01-25
影响因子：
5.6
通讯作者：
Galler, R
中科院分区：
文献类型：
--
作者：
Bonaldo, MC;Garratt, RC;Galler, R
黄热病17 D病毒（YF 17 D）具有几个特征，这些特征对于开发新的减毒活疫苗是理想的。我们接近它的发展作为一个载体的异源抗原，通过研究的体液表位的表达在E蛋白的表面的基础上，其三维结构建模的结果。该模型表明，最有希望的插入位点在β链f和g之间，该位点暴露在病毒的外表面。与蜱传脑炎病毒相比，来自黄热病病毒的E蛋白的fg环的六个残基的大缺失在二聚体界面处留下空间用于大插入而不产生空间位阻。我们已经通过插入由三重NANP重复组成的恶性疟原虫环子孢子蛋白的模型体液表位来验证这一假设。表达该插入的重组病毒（17 D/8）在每一端侧接两个甘氨酸残基，被针对模型表位的单克隆抗体特异性中和。此外，针对重组病毒产生的小鼠抗体在ELISA测定中识别寄生虫蛋白。连续传代分析证实了在病毒基因组中进行的插入的遗传稳定性，并且所得17 D/8病毒在小鼠神经毒力试验中比17 DD疫苗显著更弱。fg环属于E蛋白的二聚化结构域，位于单体之间的界面。该结构域经历低pH转变，这与病毒包膜与内体膜的融合有关。可以想象的是，由于靠近二聚体界面的插入而导致的较慢的融合速率可能延迟病毒产生的开始，从而导致宿主的较温和感染。这将解释小鼠模型中重组病毒的更减毒表型和培养细胞中的复制程度。黄热病病毒的载体能力正在进一步探索，以表达和呈递其他表位，包括介导T细胞应答的表位。(C)北京大学出版社.
The yellow fever 17D virus (YF17D) has several characteristics that are desirable for the development of new, live attenuated vaccines. We approached its development as a vector for heterologous antigens by studying the expression of a humoral epitope at the surface of the E protein based on the results of modelling its three-dimensional structure. This model indicated that the most promising insertion site is between beta-strands f and g, a site that is exposed at the external surface of the virus. The large deletion of six residues from the fg loop of the E protein,, from yellow fever virus, compared to tick-born encephalitis virus, leaves, space at the dimer interface for a large insertion without creating steric hindrance. We have tested this hypothesis by inserting a model humoral epitope from the circurnsporozoite protein of Plasmodium falciparian consisting of triple NANP repeats. Recombinant virus (17D/8) expressing this insertion flanked by two glycine residues at each end, is specifically neutralized by a monoclonal antibody to the model epitope. Furthermore, mouse antibodies raised to the recombinant virus recognize the parasite protein in an ELISA assay. Serial passage analysis confirmed the genetic stability of the insertion made in the viral genome and the resulting 17D/8 virus is significantly more attenuated in mouse neurovirulence tests than the 17DD vaccine. The fg loop belongs to the dimerization domain of the E protein and lies at the interface between monomers. This domain undergoes a low pH transition, which is related to the fusion of the viral envelope to the endosome membrane. It is conceivable that a slower rate of fusion, resulting from the insertion close to the dimer interface, may delay the onset of virus production and thereby lead to a milder infection of the host. This would account for the more attenuated phenotype of the recombinant virus in the mouse model and tower extent of replication in cultured cells. The vectorial capacity of the yellow fever virus is being further explored for the expression and presentation of other epitopes, including those mediating T-cell responses. (C) 2002 Academic Press.