Department of Biomedicine, Aarhus University, Høegh-Guldbergsgade 10, Building 1116, 8000, Aarhus C, Denmark.
Department of Biotherapeutic Discovery, H. Lundbeck A/S, Copenhagen, Denmark.
Sci Rep. 2020 Sep 3;10(1):14582. doi: 10.1038/s41598-020-71286-2.
The brain uptake of biotherapeutics for brain diseases is hindered by the blood-brain barrier (BBB). The BBB selectively regulates the transport of large molecules into the brain and thereby maintains brain homeostasis. Receptor-mediated transcytosis (RMT) is one mechanism to deliver essential proteins into the brain parenchyma. Receptors expressed in the brain endothelial cells have been explored to ferry therapeutic antibodies across the BBB in bifunctional antibody formats. In this study, we generated and characterized monoclonal antibodies (mAbs) binding to the basigin receptor, which recently has been proposed as a target for RMT across the BBB. Antibody binding properties such as affinity have been demonstrated to be important factors for transcytosis capability and efficiency. Nevertheless, studies of basigin mAb properties' effect on RMT are limited. Here we characterize different basigin mAbs for their ability to associate with and subsequently internalize human brain endothelial cells. The mAbs were profiled to determine whether receptor binding epitope and affinity affected receptor-mediated uptake efficiency. By competitive epitope binning studies, basigin mAbs were categorized into five epitope bins. mAbs from three of the epitope bins demonstrated properties required for RMT candidates judged by binding characteristics and their superior level of internalization in human brain endothelial cells.
治疗脑部疾病的生物疗法的脑部摄取受到血脑屏障 (BBB) 的阻碍。BBB 选择性地调节大分子进入大脑的运输，从而维持大脑内环境的稳定。受体介导的转胞吞作用 (RMT) 是将必需蛋白质递送到脑实质中的一种机制。已经探索了在双功能抗体形式中穿过 BBB 输送治疗性抗体的脑内皮细胞表达的受体。在这项研究中，我们生成并鉴定了与 basigin 受体结合的单克隆抗体 (mAb)，该受体最近被提议作为 RMT 穿过 BBB 的靶点。抗体结合特性，如亲和力，已被证明是转胞吞作用能力和效率的重要因素。然而，关于 basigin mAb 特性对 RMT 的影响的研究有限。在这里，我们研究了不同的 basigin mAb 与人类脑内皮细胞结合和随后内化的能力。对 mAb 进行了分析，以确定受体结合表位和亲和力是否影响受体介导的摄取效率。通过竞争性表位 binning 研究，basigin mAb 被分为五个表位 bin。通过结合特性和在人脑内皮细胞中的内化水平判断，来自三个表位 bin 的 mAb 具有 RMT 候选物所需的特性。
