Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.
Cell. 2015 Nov 19;163(5):1095-1107. doi: 10.1016/j.cell.2015.10.050. Epub 2015 Nov 6.
We screened a panel of mouse and human monoclonal antibodies (MAbs) against chikungunya virus and identified several with inhibitory activity against multiple alphaviruses. Passive transfer of broadly neutralizing MAbs protected mice against infection by chikungunya, Mayaro, and O'nyong'nyong alphaviruses. Using alanine-scanning mutagenesis, loss-of-function recombinant proteins and viruses, and multiple functional assays, we determined that broadly neutralizing MAbs block multiple steps in the viral lifecycle, including entry and egress, and bind to a conserved epitope on the B domain of the E2 glycoprotein. A 16 Å resolution cryo-electron microscopy structure of a Fab fragment bound to CHIKV E2 B domain provided an explanation for its neutralizing activity. Binding to the B domain was associated with repositioning of the A domain of E2 that enabled cross-linking of neighboring spikes. Our results suggest that B domain antigenic determinants could be targeted for vaccine or antibody therapeutic development against multiple alphaviruses of global concern.
我们筛选了一组针对基孔肯雅病毒的小鼠和人源单克隆抗体(MAbs),并鉴定出了几种对多种甲病毒具有抑制活性的抗体。将广泛中和的 MAbs 被动转移到小鼠体内,可保护其免受基孔肯雅病毒、马亚罗病毒和奥尼昂昂尼昂病毒的感染。通过丙氨酸扫描诱变、功能丧失重组蛋白和病毒以及多种功能测定,我们确定广泛中和的 MAbs 可阻断病毒生命周期中的多个步骤,包括进入和离开,并与 E2 糖蛋白 B 结构域上的保守表位结合。与 CHIKV E2 B 结构域结合的 Fab 片段的 16 Å 分辨率冷冻电镜结构为其中和活性提供了一个解释。与 B 结构域的结合与 E2 的 A 结构域的重新定位相关,从而使相邻刺突交联。我们的研究结果表明,B 结构域抗原决定簇可作为针对具有全球意义的多种甲病毒的疫苗或抗体治疗开发的靶点。