a AbbVie Bioresearch Center , 381 Plantation St., Worcester , MA.
b AbbVie Bioresearch Center , 100 Research Drive, Worcester , MA.
MAbs. 2018 Jul;10(5):765-777. doi: 10.1080/19420862.2018.1465159. Epub 2018 Jun 5.
Therapeutic monoclonal antibodies and endogenous IgG antibodies show limited uptake into the central nervous system (CNS) due to the blood-brain barrier (BBB), which regulates and controls the selective and specific transport of both exogenous and endogenous materials to the brain. The use of natural transport mechanisms, such as receptor-mediated transcytosis (RMT), to deliver antibody therapeutics into the brain have been studied in rodents and monkeys. Recent successful examples include monovalent bispecific antibodies and mono- or bivalent fusion proteins; however, these formats do not have the capability to bind to both the CNS target and the BBB transport receptor in a bivalent fashion as a canonical antibody would. Dual-variable-domain immunoglobulin (DVD-Ig) proteins offer a bispecific format where monoclonal antibody-like bivalency to both the BBB receptor and the therapeutic target is preserved, enabling independent engineering of binding affinity, potency, valency, epitope and conformation, essential for successful generation of clinical candidates for CNS applications with desired drug-like properties. Each of these parameters can affect the binding and transcytosis ability mediated by different receptors on the brain endothelium differentially, allowing exploration of diverse properties. Here, we describe generation and characterization of several different DVD-Ig proteins, specific for four different CNS targets, capable of crossing the BBB through transcytosis mediated by the transferrin receptor 1 (TfR1). After systemic administration of each DVD-Ig, we used two independent methods in parallel to observe specific uptake into the brain. An electrochemiluminescent-based sensitive quantitative assay and a semi-quantitative immunohistochemistry technique were used for brain concentration determination and biodistribution/localization in brain, respectively. Significantly enhanced brain uptake and retention was observed for all TfR1 DVD-Ig proteins regardless of the CNS target or the systemic administration route selected.
治疗性单克隆抗体和内源性 IgG 抗体由于血脑屏障（BBB）的存在，摄取量有限，无法进入中枢神经系统（CNS）。BBB 调节和控制着外源性和内源性物质向大脑的选择性和特异性转运。利用受体介导的胞吞作用（RMT）等天然转运机制将抗体治疗药物递送到大脑的方法已在啮齿动物和猴子中进行了研究。最近的成功案例包括单价双特异性抗体和单或双价融合蛋白；然而，这些形式不能像典型抗体那样以双价方式结合 CNS 靶标和 BBB 转运受体。双可变域免疫球蛋白（DVD-Ig）蛋白提供了一种双特异性形式，保留了对 BBB 受体和治疗靶标的类似单克隆抗体的双价性，从而能够独立地对结合亲和力、效力、价态、表位和构象进行工程改造，这对于成功生成具有所需药物特性的 CNS 应用的临床候选物至关重要。这些参数中的每一个都会影响不同脑内皮细胞上不同受体介导的结合和胞吞作用能力，从而可以探索不同的特性。在这里，我们描述了几种不同的 DVD-Ig 蛋白的产生和表征，这些蛋白针对四个不同的 CNS 靶标，能够通过转铁蛋白受体 1（TfR1）介导的胞吞作用穿过 BBB。在每种 DVD-Ig 全身给药后，我们使用两种独立的方法平行观察特定的脑内摄取。我们使用基于电化学发光的灵敏定量测定法和半定量免疫组织化学技术分别用于脑内浓度测定和脑内分布/定位。无论选择 CNS 靶标还是全身给药途径，所有 TfR1 DVD-Ig 蛋白均观察到显著增强的脑摄取和保留。
