H5N1亚型禽流感病毒血凝素Th和B细胞表位预测及抗原性分析

Prediction of the Th/B cell epitopes on HA of avian influenza virus (H5N1) and antigenicity analysis

目的:预测H5N1亚型禽流感病毒血凝素Th和B细胞相关抗原表位,并初步分析其抗原性。方法:依据近年H5N1亚型禽流感病毒流行趋势,下载得到相关HA蛋白氨基酸序列。进行生物信息学综合分析预测,获得Th和B细胞相关抗原表位,并比较其保守性和特异性。通过BALB/c小鼠和SPF鸡H5N1亚型禽流感病毒阳性血清,初步鉴定候选表位抗原性。结果:综合多项预测及空间构象模拟结果,我们获得了三条候选Th和B细胞表位,分别为HA141～155、HA206～223、HA302～316。候选表位处于H5N1亚型禽流感HA1蛋白序列上相对保守的区域内,且与目前流行的H5N1亚型禽流感病毒HA相应区域具有较好的一致性。而不同候选表位在BALB/c小鼠和SPF鸡H5N1亚型禽流感病毒阳性血清反应中显示了不同抗体结合能力,预示了其成为功能表位的可能。结论:所筛选的表位具有成为H5N1亚型禽流感病毒HATh和B细胞相关抗原表位的可能。本研究为深入揭示流感病毒感染与免疫机制,H5N1亚型禽流感功能表位认知及表位疫苗研究奠定了基础。

Objective： To predict Th/B cell epitopes on HA of avian influenza virus（ HSN1 ） and analyze antigenicity of the candidate epitopes. Methods： The HA amino acid sequences of AIV（H5N1 ） which were prevalent recently, were downloaded from GeneBank. The Th/B cell epitopes were predicted and analyzed by bioinformatics methods. Then, specificity and conservation of the candidate epitopes were estimated.Finally,anfigenicity of the candidate epitopes was identified by AIV（H5N1） positive serum samples of mice and SPF chicken. Results： Three Th/B cell epitopes containing HA141-155, HA206-223, HA302-316 were acquired. All the candidate epitopes were on a relatively conserved domain of HA1, and a deal of 2005-2008 AIV（HSN1 ） isolates especially the Asian ones contained the sequences. Moreover, the candidate epitopes were showed with a distinct antibody combining reactivity with the AIV（HSN1 ） positive serum of mice and SPF chicken, which inferred the predicted epitopes to be functional ones. Conclusion： The selected epitopes are able to be functional HA Th/B cell epitopes of AIV （HSN1）. Our study also establishes the foundations for the further research of influenza virus infection and immunity mechanism,the recognition of AIV （HSN1） functional epitopes and the development of epitope vaccines.