Attribute Sciences, Amgen Inc., Thousand Oaks, California, USA.
Drug Product Technologies, Amgen Inc., Thousand Oaks, California, USA.
Biotechnol Prog. 2020 Nov;36(6):e3045. doi: 10.1002/btpr.3045. Epub 2020 Aug 4.
Antibody-dependent cell-mediated cytotoxicity (ADCC) has been identified as one of the potentially critical effector functions underlying the clinical efficacy of some therapeutic immunoglobin G1 (IgG1) antibodies. It has been well established that higher levels of afucosylated N-linked glycan structures on the Fc region enhance the IgG binding affinity to the FcγIIIa receptor and lead to increased ADCC activity. However, whether terminal galactosylation of an IgG1 impacts its ADCC activity is less understood. Here, we used a new strategy for glycan enrichment and remodeling to study the impact of terminal galactose on ADCC activity for therapeutic IgG1s. Our results indicate that the degree of influence of terminal galactose on in vitro ADCC activity depends on the presence or absence of the core fucose, which is typically linked to the first N-acetyl glucosamine residue of an N-linked glycosylation core structure. Specifically, terminal galactose on afucosylated IgG1 mAbs enhanced ADCC activity with impact coefficients (ADCC%/Gal%) more than 20, but had minimal influence on ADCC activity on fucosylated structures with impact coefficient in the range of 0.1-0.2. Knowledge gained here can be used to guide product and process development activities for biotherapeutic antibodies that require effector function for efficacy, and also highlight the complexity in modulating the immune response through N-linked glycosylation of antibodies.
抗体依赖的细胞介导的细胞毒性 (ADCC) 已被确定为某些治疗性免疫球蛋白 G1 (IgG1) 抗体临床疗效的潜在关键效应功能之一。已经证实，Fc 区域上无岩藻糖的 N-连接糖基化结构的水平越高，可增强 IgG 与 FcγIIIa 受体的结合亲和力，并导致 ADCC 活性增加。然而，IgG1 末端半乳糖基化是否会影响其 ADCC 活性还不太清楚。在这里，我们使用了一种新的聚糖富集和重塑策略来研究末端半乳糖对治疗性 IgG1 的 ADCC 活性的影响。我们的结果表明，末端半乳糖对体外 ADCC 活性的影响程度取决于核心岩藻糖的存在与否，核心岩藻糖通常与 N-连接糖基化核心结构的第一个 N-乙酰葡萄糖胺残基相连。具体而言，末端半乳糖基化可增强无岩藻糖 IgG1 mAb 的 ADCC 活性，影响系数（ADCC%/Gal%）超过 20，但对半乳糖化结构的 ADCC 活性影响较小，影响系数在 0.1-0.2 范围内。此处获得的知识可用于指导需要效应功能才能发挥疗效的治疗性抗体的产品和工艺开发活动，同时还突出了通过抗体的 N-连接糖基化来调节免疫反应的复杂性。
