Harnessing the anti-inflammatory activity of extracellular sialylation of IgG.

项目摘要/摘要。 尽管免疫疗法在临床上取得了巨大的成功，但人们对免疫球蛋白G2-4的生物学相关知识知之甚少。 为IgG1干杯。我们的长期目标是了解抗体的糖基化是如何调节的，并受 免疫反应。这一应用的总体目标是检查细胞外的调节 唾液酸化免疫球蛋白，了解免疫球蛋白唾液酸化如何发挥抗炎活性。过去一段时间的研究 十年来已经阐明了IgG1糖基化的重要性，但对其贡献知之甚少。 糖基化到其他免疫球蛋白亚类或调节免疫球蛋白唾液酸化。我们最近演示了唾液酸化 在给予可溶性糖基转移酶后，炎症期间的免疫球蛋白在细胞外原位发生， 命名为B4ST6Fc。我们的中心假设是B4ST6Fc的胞外唾液酸化传递II型FcγR结合 对IgG1和IgG3有选择性的抗炎活性。我们的假设是由初步数据证实的 这里显示在研究策略部分的方法小节中。在体胞外唾液酸化 在自身抗体诱导的疾病中，肾脏或爪子中的致病小鼠免疫球蛋白可减弱两种截然不同的 自身免疫性疾病的模型。此外，我们还证明了唾液酸化的IgG1和IgG3具有抗炎作用。 体内活性和体外DC-SIGN结合。这项拟议研究的基本原理是理解 Fc糖基化对所有免疫球蛋白亚类的贡献将使人们能够对免疫球蛋白生物学有新的见解，并可能导致 以抗体为基础的创新疗法的发展。我们将测试我们的中心假设，从而实现 该应用程序的目的是通过使用生物物理的组合来追求以下特定目的 实验，以及体外和体内功能测定。 1)明确自身免疫性疾病中细胞外免疫球蛋白唾液酸化的调节。假设：B4ST6Fc 核糖底物通过唾液酸化病原性IgG1和IgG3减轻SLE肾炎 通过沉积的血小板释放。 2)确定唾液酸化免疫球蛋白抗炎活性的分子决定因素。假设：一种特定的 Ig G1和Ig G3所特有、Ig G2和Ig G4所没有的氨基酸序列，与N297结合 唾液酸化，导致DC-SIGN结合能力和抗炎活性。

Project Summary/Abstract. Despite the tremendous clinical success of immunotheraputics, little is known regarding IgG2-4 biology relative to IgG1. Our long-term goal is to understand how glycosylation of antibodies regulates, and is regulated, by immune responses. The overall objective of this application is to examine the regulation of extracellular sialylation of IgG, and understand how IgG sialylation exerts anti-inflammatory activity. Studies over the last decade have illuminated the importance of IgG1 glycosylation, little is known about the contribution of glycosylation to other IgG subclasses or the regulation of IgG sialylation. We recently demonstrated sialylation of IgG during inflammation occurs extracellularly in situ following administration of soluble glycosyltransferases, termed B4ST6Fc. Our central hypothesis is that extracellular sialylation by B4ST6Fc conveys type II FcγR binding and anti-inflammatory activity selectively to IgG1 and IgG3. Our hypothesis is informed by preliminary data shown here in the Approach subsection of the Research Strategy section. Extracellular sialylation in situ of pathogenic mouse IgG in the kidneys or paws during autoantibody-induced disease attenuates two distinct models of autoimmune disease. Further, we show sialylation of IgG1 and IgG3 results in anti-inflammatory activity in vivo, and DC-SIGN binding in vitro. The rationale that underlies the proposed research is understanding the contribution of Fc glycosylation to all IgG subclasses will enable new insights into IgG biology, and may lead to development of innovative antibody-based therapies. We will test our central hypothesis and, thereby, attain the objective of this application by pursuing the following specific aims using a combination of biophysical experiments, and in vitro and in vivo functional assays. 1) Define the regulation of extracellular IgG sialylation during autoimmune disease. Hypothesis: B4ST6Fc reduces SLE nephritis by sialylation of pathogenic IgG1 and IgG3 with the aid of nucleotide-sugar substrates released by deposited platelets. 2) Identify the molecular determinants of sialylated IgG anti-inflammatory activity. Hypothesis: a specific amino acid sequence that is unique to IgG1 and IgG3 and absent from IgG2 and IgG4, in combination with N297 sialylation, results in DC-SIGN binding ability and anti-inflammatory activity.