Preclinical studies of a MADCAM-Fc fusion protein in multiple sclerosis

描述(由申请人提供)： 多发性硬化症(MS)是一种中枢神经系统(CNS)的自身免疫性疾病，是美国年轻人中最常见的非创伤性神经残疾原因。当视神经、脑或脊髓形成炎性灶，导致脱髓鞘和邻近轴突受损时，疾病就会恶化。黏附分子介导的白细胞从血流到中枢神经系统的迁移是多发性硬化病变形成的关键步骤。目前的提议检验了我们的假设，即靶向阻断特定的黏附分子相互作用(在CNS浸润性T细胞上表达的a4b7和在发炎的CNS血管上表达的MAdCAM-1之间)将防止MS(实验性自身免疫性脑脊髓炎或EAE)小鼠模型中自身免疫性脱髓鞘的恶化。为此，我们设计了一种嵌合融合蛋白(MAdCAM-1-Fc)，由MAdCAM-1-Fc的胞外区与小鼠免疫球蛋白重链的Fc区连接组成。该试剂可阻止MAdCAM-1与表达A4b7的T细胞结合。我们将确定全身应用MAdCAM-1-Fc或对照融合蛋白是否能抑制EAE的复发或进展。此外，在安全性测试中，我们将给感染甲型病毒的小鼠注射MAdCAM-1-Fc，并确定该治疗是否阻碍病毒清除和/或触发中枢神经系统潜伏病毒的重新激活。1.研究慢性实验性自身免疫性脑脊髓炎(EAE)小鼠复发及慢性实验性脑脊髓炎(EAE)发病过程中中枢神经系统CD4+T细胞表面a4b7及其同源配体MAdCAM-1的时空表达。此外，还设计了其他实验，以检测诱导髓鞘特异性效应细胞上的a4b7和中枢神经系统内皮细胞上的MAdCAM-1表达的炎症因子。2.研究4b7受体阻滞剂对复发性和慢性EAE模型的治疗效果。我们将比较一种新型的MAdCAM-1-Fc重组融合蛋白(特异性阻断a4b7整合素)与其他黏附分子阻滞剂在病程不同时间点的治疗效果。3.研究A4b7受体阻滞剂对小鼠中枢神经系统急性病毒感染和再激活潜伏病毒感染的影响。我们将使用甲型病毒感染的小鼠模型来比较MAdCAM-1-Fc和其他融合蛋白在抗病毒免疫和免疫监控方面的效果。

DESCRIPTION (provided by applicant): Multiple Sclerosis (MS), an autoimmune disease of the central nervous system (CNS), is the most common non-traumatic cause of neurological disability among young adults in the United States. Exacerbations of the disease occur when inflammatory foci form in the optic nerves, brain or spinal cord, resulting in demyelination and damage to neighboring axons. A critical step in the formation of MS lesions is adhesion molecule mediated transmigration of leukocytes from the bloodstream into the CNS. The current proposal tests our hypothesis that targeted blockade of a particular adhesion molecule interaction (between a4b7, expressed on CNS-infiltrating T cells, and MAdCAM-1, expressed on inflamed CNS blood vessels) will prevent exacerbations of autoimmune demyelination in a mouse model of MS (experimental autoimmune encephalomyelitis or EAE). To do so, we have engineered a chimeric fusion protein (MAdCAM-1-Fc), composed of the extracellular domain of MAdCAM-1-Fc linked to the Fc region of mouse immunoglobulin heavy chain. This reagent prevents MAdCAM-1 from binding a4b7 expressing T cells. We will determine whether systemic administration of MAdCAM-1-Fc or control fusion proteins suppresses relapses or progression of EAE. Furthermore, in a test of its safety, we will administer MAdCAM-1-Fc to mice infected with an alphavirus and determine whether the treatment impedes viral clearance and/ or triggers reactivation of latent virus in the CNS. The specific aims of our proposal are as follows: 1. To study the temporal and spatial expression of a4b7 on CNS infiltrating CD4+ T cells and its cognate ligand, MAdCAM-1, on CNS vascular endothelium during the course of relapsing and chronic experimental autoimmune encephalomyelitis (EAE) in mice. Additional experiments are designed to examine the inflammatory factors that induce expression of a4b7 on myelin-specific effector cells and MAdCAM-1 on CNS endothelial cells. 2. To investigate the therapeutic consequences of a4b7 blockade in both relapsing and chronic EAE models. We will compare the therapeutic efficacy of a novel MAdCAM-1-Fc recombinant fusion protein (that specifically blocks a4b7 integrin) versus other adhesion molecule blocking agents, when given at different time points in the disease course. 3. To characterize the effects of systemic a4b7 blockade on acute viral infection of the CNS and reactivated latent viral infection in mice. We will use a mouse model of alphavirus infection to compare the effects of MAdCAM-1-Fc and other fusion proteins on anti-viral immunity and immunosurveillance.