啮齿动物抗体库中可变区胚系片段配对决定的受限表位特异性。
Restricted epitope specificity determined by variable region germline segment pairing in rodent antibody repertoires.
机构信息
Department of Antibody Engineering, Genentech, South San Francisco, CA, USA.
Department of Molecular Biology, Genentech, South San Francisco, CA, USA.
出版信息
MAbs. 2020 Jan-Dec;12(1):1722541. doi: 10.1080/19420862.2020.1722541.
Antibodies from B-cell clonal lineages share sequence and structural properties as well as epitope specificity. Clonally unrelated antibodies can similarly share sequence and specificity properties and are said to be convergent. Convergent antibody responses against several antigens have been described in humans and mice and include different classes of shared sequence features. In particular, some antigens and epitopes can induce convergent responses of clonally unrelated antibodies with restricted heavy (V) and light (V) chain variable region germline segment usage without similarity in the heavy chain third complementarity-determining region (CDR H3), a critical specificity determinant. Whether these V germline segment-restricted responses reflect a general epitope specificity restriction of antibodies with shared V/V pairing is not known. Here, we investigated this question by determining patterns of antigen binding competition between clonally unrelated antigen-specific rat antibodies from paired-chain deep sequencing datasets selected based solely on V/V pairing. We found that antibodies with shared V/V germline segment pairings but divergent CDR H3 sequences almost invariably have restricted epitope specificity indicated by shared binding competition patterns. This epitope restriction included 82 of 85 clonally unrelated antibodies with 13 different V/V pairings binding in 8 epitope groups in 2 antigens. The corollary that antibodies with shared V/V pairing and epitope-restricted binding can accommodate widely divergent CDR H3 sequences was confirmed by in vitro selection of variants of anti-human epidermal growth factor receptor 2 antibodies known to mediate critical antigen interactions through CDR H3. Our results show that restricted epitope specificity determined by V/V germline segment pairing is a general property of rodent antigen-specific antibodies.
B 细胞克隆谱系的抗体具有相同的序列和结构特性以及表位特异性。非克隆相关的抗体也可以具有相同的序列和特异性特性,被称为趋同。在人类和小鼠中已经描述了针对几种抗原的趋同抗体反应,包括具有不同共享序列特征的不同类别。特别是,一些抗原和表位可以诱导具有有限重(V)和轻(V)链可变区胚系片段使用的非克隆相关抗体的趋同反应,而重链第三互补决定区(CDR H3)没有相似性,这是一个关键的特异性决定因素。这些 V 胚系片段受限的反应是否反映了具有共享 V/V 配对的抗体的一般表位特异性限制尚不清楚。在这里,我们通过确定基于仅基于 V/V 配对选择的配对链深度测序数据集的非克隆相关抗原特异性大鼠抗体之间的抗原结合竞争模式来研究这个问题。我们发现,具有共享 V/V 胚系片段配对但 CDR H3 序列不同的抗体几乎总是具有受限的表位特异性,这表明具有共享的结合竞争模式。这种表位限制包括 85 个具有 13 种不同 V/V 配对的 82 个非克隆相关抗体,这些抗体在 2 种抗原中的 8 个表位组中结合。具有共享 V/V 配对和表位受限结合的抗体可以容纳广泛不同的 CDR H3 序列的推论通过体外选择已知通过 CDR H3 介导关键抗原相互作用的抗人表皮生长因子受体 2 抗体的变体得到了证实。我们的结果表明,由 V/V 胚系片段配对决定的受限表位特异性是啮齿动物抗原特异性抗体的普遍特性。