Glycoengineering of antibodies to modulate immune functions

项目摘要 抗体是一类重要的治疗剂，其广泛用于治疗癌症、自身免疫性疾病和/或免疫性疾病。 疾病和传染病。令人信服的实验数据表明，Fc糖基化是一个重要的因素。 调节抗体效应子功能的关键结构决定因子，包括抗体依赖性 细胞毒性（ADCC）、补体依赖性细胞毒性（CDC）、细胞凋亡激活和抗- 炎症活动。然而，在理解抗体糖基化的功能作用方面的进展， 受到Fc糖基化的巨大结构异质性的阻碍。为了解决这个问题，我们 开发了一种化学酶促方法，该方法允许位点特异性Fc和Fab聚糖重塑以产生 均质抗体糖型。在此应用中，我们建议利用位点特异性化学酶促 聚糖重塑方法作为一个关键的平台技术，以解决三个重要的问题， 抗体功能，如以下三个具体目标所强调的。目的1是了解Fc 糖基化通过选择性修饰核心岩藻糖， 进行结构研究，并通过合成新的糖型，与Fc受体结合， ADCC测定。目的2是评估Fc聚糖的位点特异性唾液酸化如何影响抗体的抗- 通过构建不对称唾液酸化或多重唾液酸化糖型， 动物研究。目的3：构建具有补体依赖性细胞毒活性（CDC）的 结构上明确的抗人IgG/鼠李糖抗原-抗体缀合物，以募集天然IgG和IgM抗体 在流通。这些研究将在糖免疫学方面产生重要的新知识，这将有助于 开发更有效的基于抗体的疗法。

Project Summary Antibodies are an important class of therapeutics that are widely used for treatment of cancer, autoimmune diseases, and infectious diseases. Compelling experimental data have demonstrated that Fc glycosylation is a critical structural determinant for modulating antibody’s effector functions, including antibody-dependent cellular cytotoxicity (ADCC), complement-dependent cytotoxicity (CDC), activation of apoptosis, and anti- inflammatory activities. However, progress in understanding the functional roles of antibody glycosylation is hampered by the tremendous structural heterogeneity of Fc glycosylation. To address this problem, we have developed a chemoenzymatic method that permits site-specific Fc and Fab glycan remodeling to generate homogeneous antibody glycoforms. In ths application, we propose to exploit the site-specific chemoenzymatic glycan remodeling method as a key platform technology to address three important questions related to antibody functions, as highlighted in the following three specific aims. Aim 1 is to understand how Fc glycosylation modulate Fc receptor binding and ADCC activity by selective modification of the core fucose, by performing structural studies, and by synthesizing novel glycoforms, coupled with Fc receptor binding and ADCC assays. Aim 2 is to evaluate how site-specific sialylation of Fc glycans affects antibody’s anti- inflammatory activity by constructing asymmetrically sialylated or multiply sialylated glycoforms, coupled with animal studies. Aim 3 is to augment antibody’s complement-dependent cytotoxicity (CDC) by constructing structurally well-defined Gal/rhamnose antigen-antibody conjugates to recruit natural IgG and IgM antibodies in circulation. These studies will yield important new knowledge in glyco-immunology, which will facilitate the development of more effective antibody-based therapeutics.