Conserved stem fragment from H3 influenza hemagglutinin elicits cross-clade neutralizing antibodies through stalk-targeted blocking of conformational change during membrane fusion
Conserved stem fragment from H3 influenza hemagglutinin elicits cross-clade neutralizing antibodies through stalk-targeted blocking of conformational change during membrane fusion
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DOI：
10.1016/j.imlet.2016.02.006
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发表时间：
2016-04-01
影响因子：
4.4
通讯作者：
Shan, Yaming
中科院分区：
文献类型：
--
作者：
Gong, Xin;Yin, He;Shan, Yaming
目前可用的流感疫苗通常由于病毒序列的突变性和保护性免疫期间的构象变化而不能引发/加强广泛中和抗体，从而限制了它们的功效。这个问题需要通过进一步了解中和的机制和在膜融合过程中找到所需的中和位点来解决。这项研究特别关注H3 N2亚型病毒，自1968年流感大流行以来，H3 N2亚型一直是人类流感相关发病率和死亡率的主要来源。通过序列比对和表位预测，发现了一系列高度保守的茎片段（跨越47年），并与钥孔血蓝蛋白（KLH）蛋白偶联。通过应用组合展示文库和晶体结构建模，鉴定了位于HA颈的转折点处的干片段免疫原，所述干片段免疫原在与B-和T-细胞表位的膜融合期间经历构象变化。在使用多抗原肽（MAP）系统合成最佳茎片段后，在动物免疫后观察到针对来自组2流感病毒H3亚型的毒株的强体液免疫应答和交叉进化枝中和活性。通过用酸旁路处理检测核蛋白免疫荧光，针对茎片段的MAP 4免疫原提出的抗血清显示出抑制HA在茎靶向病毒中和中的构象变化的潜力。这个保守的茎片段的鉴定为利用这个位点的脆弱性在治疗和疫苗设计提供了巨大的潜力。(C)2016年欧洲免疫学会联合会。Elsevier B. V.出版，保留所有权利。
Currently available influenza vaccines typically fail to elicit/boost broadly neutralizing antibodies due to the mutability of virus sequences and conformational changes during protective immunity, thereby limiting their efficacy. This problem needs to be addressed by further understanding the mechanisms of neutralization and finding the desired neutralizing site during membrane fusion. This study specifically focused on viruses of the H3N2 subtype, which have persisted as a principal source of influenza-related morbidity and mortality in humans since the 1968 influenza pandemic. Through sequence alignment and epitope prediction, a series of highly conserved stem fragments (spanning 47 years) were found and coupled to the Keyhole Limpet Hemocyanin (KLH) protein. By application of a combinatorial display library and crystal structure modeling, a stem fragment immunogen, located at the turning point of the HA neck undergoing conformational change during membrane fusion with both B- and T-cell epitopes, was identified. After synthesis of the optimal stem fragment using a multiple antigen peptide (MAP) system, strong humoral immune responses and cross-clade neutralizing activities against strains from the H3 subtype of group 2 influenza viruses after animal immunizations were observed. By detection of nuclear protein immunofluorescence with acid bypass treatment, antisera raised against MAP4 immunogens of the stem fragment showed the potential to inhibit the conformational change of HA in stem-targeted virus neutralization. The identification of this conserved stem fragment provides great potential for exploitation of this site of vulnerability in therapeutic and vaccine design. (C) 2016 European Federation of Immunological Societies. Published by Elsevier B.V. All rights reserved.