ABSTRACT

The terminal sugars of Fc glycans can influence the Fc-dependent biological activities of monoclonal antibody therapeutics. Afucosylated N-glycans have been shown to significantly alter binding to FcγRIIIa and affect antibody-dependent cell-mediated cytotoxicity (ADCC). Therefore, in order to maintain and ensure safety and efficacy for antibodies whose predominant mechanism of action (MOA) is ADCC, afucosylation is routinely monitored and controlled within appropriate limits. However, it is unclear how the composition and levels of afucosylated N-glycans can modulate the biological activities for a recombinant antibody whose target is not a cell surface receptor, as is the case with ADCC. The impact of different types and varying levels of enriched afucosylated N-glycan species on the in vitro bioactivities is assessed for an antibody whose target is aggregated amyloid beta (Aβ). While either the presence of complex biantennary or high mannose afucosylated glycoforms significantly increased FcγRIIIa binding activity compared to fucosylated glycoforms, they did not similarly increase aggregated Aβ uptake activity mediated by different effector cells. These experiments suggest that afucosylated N-glycans are not critical for the in vitro phagocytic activity of a recombinant antibody whose target is aggregated Aβ and uses Fc effector function as part of its MOA.

摘要

Fc聚糖的末端糖可影响单克隆抗体治疗剂的Fc依赖性生物学活性。已经显示，无岩藻糖基化的N-聚糖显着改变与FcγRIIIa的结合并影响抗体依赖性细胞介导的细胞毒性（ADCC）。因此，为了维持和确保其主要作用机制（MOA）为ADCC的抗体的安全性和有效性，常规检测岩藻糖基化并将其控制在适当的范围内。然而，尚不清楚岩藻糖基化的N-聚糖的组成和水平如何调节其靶标不是细胞表面受体的重组抗体的生物学活性，就像ADCC的情况一样。不同类型和不同水平富集的岩藻糖基化N-聚糖种类对体外的影响评估其靶标是聚集的淀粉样蛋白β（Aβ）的抗体的生物活性。尽管与岩藻糖基化糖型相比，复杂双天线或高甘露糖岩藻糖基化糖型的存在均显着增加了FcγRIIIa的结合活性，但它们并没有类似地增加由不同效应细胞介导的聚集Aβ摄取活性。这些实验表明，岩藻糖基化的N-聚糖对于重组抗体的体外吞噬活性不是至关重要的，所述重组抗体的靶标是聚集的Aβ，并且使用Fc效应子功能作为其MOA的一部分。