A Potent Neutralizing Site III-Specific Human Antibody Neutralizes Human Metapneumovirus In Vivo
A Potent Neutralizing Site III-Specific Human Antibody Neutralizes Human Metapneumovirus In Vivo
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DOI：
10.1128/jvi.00342-19
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发表时间：
2019-10-01
影响因子：
5.4
通讯作者：
Mousa, Jarrod J.
中科院分区：
文献类型：
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作者：
Bar-Peled, Yael;Diaz, Darren;Mousa, Jarrod J.
人类偏肺病毒（hMPV）是儿童病毒性下呼吸道感染的主要原因。针对 hMPV 的中和抗体的唯一目标是融合 (F) 蛋白，这是一种介导病毒-细胞膜融合的 I 类病毒融合蛋白。已分离出几种可中和 hMPV 的单克隆抗体 (mAb)；然而，确定 hMPV F 蛋白上介导此类中和抗体生成的抗原位点将有助于有效的疫苗设计。在本报告中，描述了四种新型人类单克隆抗体（MPV196、MPV201、MPV314 和 MPV364）的分离和表征。在四种 mAb 中，MPV364 被发现是体外最有效的中和 mAb。单体和三聚体 hMPV F 的结合研究表明，与其他三种 mAb 相比，MPV364 对单体 hMPV F 的结合亲和力最弱，但三聚体 hMPV F 的结合实验显示结合亲和力差异有限，表明 MPV364 靶向包含两个原聚体的抗原位点。表位分箱研究表明，MPV364 靶向 hMPV F 蛋白上的抗原位点 III，并与先前发现的单克隆抗体 MPE8 和 25P13 竞争结合，这两种抗体均与呼吸道合胞病毒 (RSV) F 蛋白发生交叉反应。然而，MPV364 不与 RSV F 蛋白发生交叉反应，并且竞争谱表明它与 hMPV F 蛋白的结合姿势与 mAb MPE8 和 25P13 略有不同。 MPV364 在体内进行了进一步评估，结果显示可显着减少 BALB/c 小鼠肺部的病毒复制。总体而言，这些数据揭示了 hMPV F 蛋白抗原位点 III 附近的一个新结合区域，可引发有效的中和 hMPV F 特异性单克隆抗体，并提供一组新的中和单克隆抗体，这些单克隆抗体是治疗开发的候选药物。尽管 hMPV 是儿童下呼吸道感染的主要原因，但了解人类偏肺病毒 (hMPV) 免疫反应的进展却相对滞后。在本报告中，我们通过分离一组针对 hMPV F 蛋白的人类单克隆抗体来推进该领域的发展。 MPV364 是一种有效的中和单克隆抗体，它靶向 hMPV F 蛋白上的抗原位点 III，并将两个原聚体整合到其表位中，但与之前发现的位点 III 单克隆抗体不同，它不与 RSV F 蛋白发生交叉反应。我们进一步在体内检查了 MPV364，发现它限制了 BALB/c 小鼠中的病毒复制。总而言之，这些数据为治疗开发提供了新的 mAb 候选药物，并为 hMPV 疫苗开发提供了见解。
Human metapneumovirus (hMPV) is a leading cause of viral lower respiratory tract infection in children. The sole target of neutralizing antibodies targeting hMPV is the fusion (F) protein, a class I viral fusion protein mediating virus-cell membrane fusion. There have been several monoclonal antibodies (mAbs) isolated that neutralize hMPV; however, determining the antigenic sites on the hMPV F protein mediating such neutralizing antibody generation would assist efforts for effective vaccine design. In this report, the isolation and characterization of four new human mAbs, termed MPV196, MPV201, MPV314, and MPV364, are described. Among the four mAbs, MPV364 was found to be the most potent neutralizing mAb in vitro. Binding studies with monomeric and trimeric hMPV F revealed that MPV364 had the weakest binding affinity for monomeric hMPV F compared to the other three mAbs, yet binding experiments with trimeric hMPV F showed limited differences in binding affinity, suggesting that MPV364 targets an antigenic site incorporating two protomers. Epitope binning studies showed that MPV364 targets antigenic site III on the hMPV F protein and competes for binding with previously discovered mAbs MPE8 and 25P13, both of which cross-react with the respiratory syncytial virus (RSV) F protein. However, MPV364 does not cross-react with the RSV F protein, and the competition profile suggests that it binds to the hMPV F protein in a binding pose slightly shifted from mAbs MPE8 and 25P13. MPV364 was further assessed in vivo and was shown to substantially reduce viral replication in the lungs of BALB/c mice. Overall, these data reveal a new binding region near antigenic site III of the hMPV F protein that elicits potent neutralizing hMPV F-specific mAbs and provide a new panel of neutralizing mAbs that are candidates for therapeutic development.IMPORTANCE Recent progress in understanding the human immune response to respiratory syncytial virus has paved the way for new vaccine antigens and therapeutics to prevent and treat disease. Progress toward understanding the immune response to human metapneumovirus (hMPV) has lagged behind, although hMPV is a leading cause of lower respiratory tract infection in children. In this report, we advanced the field by isolating a panel of human mAbs to the hMPV F protein. One potent neutralizing mAb, MPV364, targets antigenic site III on the hMPV F protein and incorporates two protomers into its epitope yet is unique from previously discovered site III mAbs, as it does not cross-react with the RSV F protein. We further examined MPV364 in vivo and found that it limits viral replication in BALB/c mice. Altogether, these data provide new mAb candidates for therapeutic development and provide insights into hMPV vaccine development.