Development of Foot-and-Mouth Disease Virus-Neutralizing Monoclonal Antibodies Derived From Plasmablasts of Infected Cattle and Their Germline Gene Usage
Development of Foot-and-Mouth Disease Virus-Neutralizing Monoclonal Antibodies Derived From Plasmablasts of Infected Cattle and Their Germline Gene Usage
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DOI：
10.3389/fimmu.2019.02870
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发表时间：
2019-12-06
影响因子：
7.3
通讯作者：
Liu, Zaixin
中科院分区：
文献类型：
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作者：
Li, Kun;Wang, Sheng;Liu, Zaixin
牛对口蹄疫病毒(FMDV)易感，中和抗体是预防该物种感染口蹄疫病毒的关键。然而，关于口蹄疫病毒特异性单抗识别的宿主特异性抗原结构以及在自然宿主牛中产生的单抗的功能特性，还需要更多的信息。在此，我们从三只感染口蹄疫病毒的牛身上鉴定了55株来源于浆母细胞的单抗，并通过单B细胞抗体技术获得了28株口蹄疫病毒中和抗体。中和单抗(27/28)主要识别的构象表位不同于鼠源单抗所定义的口蹄疫病毒免疫优势抗原位点1。在这些口蹄疫病毒中和单抗中，有13个单抗对O型口蹄疫病毒的三种拓扑型(ME-SA、SEA和CAXAY拓扑型)表现出内源性广谱中和活性。此外，所有这些内源型广中和抗体都与感染或接种口蹄疫病毒的牛的血清竞争，这表明它们与天然优势表位结合，阻断酶联免疫吸附试验显示。我们进一步分析了55株口蹄疫病毒特异性单抗的种系V(D)J基因使用情况，发现含有超长HCDR3的牛免疫球蛋白抗体仅限于种系基因片段V-H1-7*02的使用。此外，在所有超长HCDR3抗体中均可观察到V-H1-7*02和V(L)1-47*01或1-52*01的限制性种系基因片段。此外，HCDR3较长的抗体更倾向于显示口蹄疫病毒的中和活性。本研究提供了一种筛选口蹄疫病毒特异性牛单抗的新方法，为研究口蹄疫病毒的抗原结构和变异提供了最有用的工具。
Cattle are susceptible to foot-and-mouth disease virus (FMDV), and neutralizing antibodies are critical for protection against FMDV infection in this species. However, more information is needed on the host specific antigenic structure recognized by the FMDV-specific monoclonal antibodies (mAbs) and on the functional properties of the mAb that are produced in the natural host, cattle. Herein, we characterized 55 plasmablast-derived mAbs from three FMDV-infected cattle and obtained 28 FMDV-neutralizing antibodies by the single B cell antibody technique. The neutralizing mAbs (27/28) mainly recognized conformational epitopes that differ from the well-characterized immunodominant antigenic site 1 of FMDV as defined by murine mAbs. Of these FMDV-neutralizing mAbs, 13 mAbs showed intra-type broadly neutralizing activity against the three topotypes of FMDV serotype O (ME-SA, SEA, and Cathay topotypes). Moreover, all these intra-type broadly neutralizing antibodies competed with sera from FMDV infected or vaccinated cattle, which indicates their binding to native dominant epitopes, as revealed by a blocking ELISA. We further analyzed the germline V(D)J gene usage of the 55 FMDV-specific mAbs and found cattle IgG antibodies containing ultralong HCDR3 were exclusively restricted to usage of the germline gene segment V-H 1-7*02. In addition, the restricted germline gene segments of V-H 1-7*02 and V(L)1-47*01 or 1-52*01 pairing were observed in all IgG antibodies with ultralong HCDR3. Furthermore, antibodies with longer HCDR3 were more inclined to display FMDV-neutralizing activity. This study presents a novel method for screening FMDV-specific cattle mAbs which then provide the most useful tools for studying FMDV antigenic structure and variation.