Examining IgG4 sialylation as a gain of function post-translation modification in IgG4-related diseases

项目概要/摘要。 IgG 4相关疾病（IgG 4-RDs）是一个以纤维化为特征的相关自身炎症性疾病家族。 病变由CD 4 + T细胞和IgG 4+浆细胞组成，寡克隆IgG 4显著升高。然而，在这方面， IgG 4抗体是否有助于IgG 4-RD病理学仍不清楚。尽管有巨大的临床 尽管免疫治疗取得了成功，但关于IgG 4相对于IgG 1的生物学知之甚少。我们的长期目标是 了解糖基化对抗体生物学的作用和调节，最终调节抗体效应子， 在体外和体内发挥作用。本申请的总体目标是全面剖析细胞毒性 唾液酸化IgG 4的活性。我们的中心假设是IgG 4-RD中的自身抗原特异性IgG 4是唾液酸化的， 有助于IgG 4-RD的病理学。我们的方法结合了来自IgG 4-RD血清的特征性IgG 和健康患者，同时在受体结合和效应器功能中精确检查糖工程化IgG 4 测定。 我们的假设是由研究策略的方法小节中显示的初步数据提供的 科.所提出的研究的基本原理是了解IgG 4如何介导细胞毒性效应物 功能将使新的见解IgG生物学，并可能导致开发创新的抗体为基础的 治疗我们将测试我们的中心假设，从而通过追求以下目标来实现本申请的目标： 以下三个具体的目标，使用生物物理实验的组合，并在体外和体内功能 测定。 1)定义IgG 4-RD中总IgG和自身抗原特异性IgG的糖基化和Fcγ Rs结合特征。 假设：唾液酸化使FcγR能够与IgG 4结合。 2)体外检测唾液酸化IgG 4的效应子功能。假设：唾液酸化IgG 4介导效应子 细胞特异性促炎效应子功能。 3)测定唾液酸化IgG 4的体内效应子功能。假设：唾液酸化IgG 4发挥促- 体内炎症效应子功能。 这一建议预计将具有广泛的临床意义，从IgG 4滴度升高的疾病， 与病理学或解决方案以及免疫治疗剂的设计相关，并代表了 通过强调IgG 4的细胞毒性能力而实质性地偏离现状。

Project Summary/Abstract. IgG4-related diseases (IgG4-RDs) are a family of related autoinflammatory diseases characterized by fibrotic lesions comprised of CD4+ T cells and IgG4+ plasma cells, and markedly elevated oligoclonal IgG4. However, whether IgG4 antibodies contribute to IgG4-RD pathology remains unclear. Despite the tremendous clinical success of immunotheraputics, little is known regarding IgG4 biology relative to IgG1. Our long-term goals are to understand the role and regulation of glycosylation to antibody biology, to ultimately modulate antibody effector functions in vitro and in vivo. The overall objective of this application is to comprehensively dissect cytotoxic activity of sialylated IgG4. Our central hypothesis is autoantigen-specific IgG4 in IgG4-RD is sialylated, and contributes to the pathology Of IgG4-RD. Our approach combines characterizing IgG from the sera of IgG4-RD and healthy patients, while examining precisely glycoengineered IgG4 in receptor binding and effector function assays. Our hypothesis is informed by preliminary data shown here in the Approach subsection of the Research Strategy section. The rationale that underlies the proposed research is understanding how IgG4 mediate cytotoxic effector function 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 three specific aims using a combination of biophysical experiments, and in vitro and in vivo functional assays. 1) Define the glycosylation and FcγRs-binding profiles of total and autoantigen-specific IgG in IgG4-RD. Hypothesis: Sialylation enables FcγR binding by IgG4. 2) Examine the effector functions of sialylated IgG4 in vitro. Hypothesis: Sialylated IgG4 mediates effector cell-specific pro-inflammatory effector functions. 3) Determine the in vivo effector functions of sialylated IgG4. Hypothesis: Sialylated IgG4 exerts pro- inflammatory effector functions in vivo. This proposal is expected to have broad clinical implications, ranging from diseases where elevated IgG4 titers are associated in the pathology or resolution, as well as to design of immunotherapeutics, and represents a substantive departure from the status quo by underscoring the cytotoxic capacity of IgG4.