■N-糖基化是一种翻译后修饰,对单克隆抗体(mAb)的开发非常重要,因为它调节它们的生物活性,特别是在免疫效应子功能方面。虽然通常以Fc水平添加,大约15-25%的循环抗体在Fab结构域中也表现出糖基化。据我们所知,西妥昔单抗(Erbitux®)是唯一的呈现Fab糖基化的治疗性抗体,其在世界范围内被批准靶向表皮生长因子受体,用于治疗转移性结直肠癌和头颈癌。此外,它可以引发抗体依赖性细胞毒性(ADCC),通常受Fc水平的N-糖基化影响的反应。然而,Fab糖基化在西妥昔单抗中的作用尚不清楚.因此,本研究旨在探讨Fab糖基化对西妥昔单抗构象行为的结构作用。
■该研究是通过加速分子动力学模拟进行的。将市售西妥昔单抗与其没有Fab糖基化的形式进行比较,并评估结构描述符以建立构象差异。
■结果清楚地显示了Fab糖基化与可能调节抗体构象自由的结构描述符之间的相关性,可能影响Fc效应子功能,并表明Fab糖基化对与FcγRIIIa的相互作用具有负面影响。
■西妥昔单抗的Fab糖基化是生物仿制药开发的最关键挑战,但是,在这项工作中强调的差异,关于其非糖基化形式可以提高知识,也代表了一个很好的机会,以发展新的生物治疗策略。
UNASSIGNED: N-glycosylation is a post-translational modification that is highly important for the development of monoclonal antibodies (mAbs), as it regulates their biological activity, particularly in terms of immune effector functions. While typically added at the Fc level, approximately 15-25% of circulating antibodies exhibit glycosylation in the Fab domains as well. To the best of our knowledge, cetuximab (Erbitux®) is the only therapeutic antibody presenting Fab glycosylation approved world-wide targeting the epidermal growth factor receptor for the treatment of metastatic-colorectal and head and neck cancers. Additionally, it can trigger antibody-dependent cell cytotoxicity (ADCC), a response that typically is influenced by N-glycosylation at Fc level. However, the role of Fab glycosylation in cetuximab remains poorly understood. Hence, this study aims to investigate the structural role of Fab glycosylation on the conformational behavior of cetuximab.
UNASSIGNED: The study was performed in silico via accelerated molecular dynamics simulations. The commercial cetuximab was compared to its form without Fab glycosylation and structural descriptors were evaluated to establish conformational differences.
UNASSIGNED: The results clearly show a correlation between the Fab glycosylation and structural descriptors that may modulate the conformational freedom of the antibody, potentially affecting Fc effector functions, and suggesting a negative role of Fab glycosylation on the interaction with FcγRIIIa.
UNASSIGNED: Fab glycosylation of cetuximab is the most critical challenge for biosimilar development, but the differences highlighted in this work with respect to its aglycosylated form can improve the knowledge and represent also a great opportunity to develop novel strategies of biotherapeutics.