Use of Bispecific Antibody for Treating Non-obese Diabetes

描述(申请人提供)：成熟T淋巴细胞的激活是一个多步骤的过程，既需要抗原特异性的TCR复合体的触发，也需要通过CD28-CD80/CD86途径介导的共同刺激。CTLA-4是T细胞活化的关键抑制物，CTLA-4基因敲除小鼠的致死性淋巴增殖证明了这一点。这些信号通路在T细胞内稳态中起主要作用，控制这些信号通路已成为抑制自身免疫的一种有效策略，并已应用于临床。在过去，耐药基因产生的双特异性抗体(BsAb)具有TSHR和CTLA-4的特异性。BsAb的抗TSHR部分可与表达TSHR的甲状腺组织结合，使抗CTLA-4部分与攻击T细胞上表达的CTLA-4结合。我们的结果表明，使用该BsAb可以诱导免疫耐受，抑制自身免疫性甲状腺炎。这种疾病抑制与CD4+CD25+Treg细胞亚群的选择性扩增有关。这些结果支持靶向CTLA-4参与可以导致Treg细胞选择性扩张的观点，该细胞可以介导对特定自身抗原的持续性低反应性。最近，用CD11c(一种树突状细胞表面标记)和CTLA-4特异性BsAb包被抗原致敏的DC，对桥本甲状腺炎和1型糖尿病也有类似的保护作用。因此，CTLA-4与活化的T细胞的靶向结合可为抑制NOD小鼠1型糖尿病模型的自身免疫提供有效的手段。 基于这些观察结果，该公司推测：“CTLA-4结合抗原特异性T细胞受体(TCR)连接可用于下调致病的自身反应性T效应细胞(”TJeff“)的反应，同时诱导能够抑制TJeff功能的Tregs，作为一种靶向治疗手段：i)防止T1D的发展；以及ii)稳定或改善正在进行的T1D。”为了验证这一假设，耐受性基因公司将开发一种BsAb，它可以通过GLUT2选择性地靶向小鼠的β细胞，并通过靶向CTLA-4参与非肥胖糖尿病(NOD)小鼠的自发性1型糖尿病(NOD)小鼠来下调β细胞渗透的T细胞。 AIM-1。抗小鼠GLUT2和CTLA-4单抗的构建及鉴定 AIM-2。检测抗小鼠GLUT2-抗CTLA-4单抗对T1D的抑制作用。 可用于特异性抑制、稳定或逆转1型糖尿病的BsAb的产生将对开发人类1型糖尿病的新疗法具有重要的临床意义。 公共卫生相关性：自身免疫性疾病是困扰美国的第三大类疾病，其中最常见的疾病影响着超过850万美国人。免疫介导性疾病的负担是惊人的。仅在美国，这些条件就导致了超过1000亿美元的直接和间接成本。现有的治疗自身免疫性疾病的临床方法依赖于免疫抑制药物的管理，这些药物会导致抑制整个免疫系统。这种反应使患者容易受到多种感染性病原体的影响。在耐受基因公司的应用中，该公司提议测试特定的治疗方法，旨在恢复免疫调节，并最初使用一种用于治疗I型糖尿病的专利双特异性抗体，仅下调异常的免疫反应。这项技术不仅对I型糖尿病的治疗工作具有重大意义，而且对美国的其他各种自身免疫性疾病也具有重要意义，包括系统性红斑狼疮(SLE)、类风湿性关节炎、多发性硬化症、格雷夫氏甲状腺疾病、桥本甲状腺炎等。

DESCRIPTION (provided by applicant): Activation of mature T lymphocytes is a multi-step process requiring both Ag-specific triggering of the TCR complex and co-stimulation mediated through the CD28-CD80/CD86 pathway. CTLA-4 is a critical inhibitor of T cell activation as evidenced by the lethal lympho-proliferation seen in CTLA-4 knockout mice. These signaling pathways play a primary role in T cell homeostasis and manipulating these pathways has emerged as a powerful strategy to suppress autoimmunity with clinical applications. In the past, Tolerogenics generated bispecific antibodies (BsAb) with specificities for TSHR and CTLA-4. The anti-TSHR portion of the BsAb could bind to the TSHR-expressing thyroid tissue leaving the anti-CTLA-4 portion to engage CTLA-4 expressed on the attacking T cells. Our results showed that using this BsAb tolerance could be induced and autoimmune thyroiditis suppressed. The disease suppression was associated with selective expansion of a subpopulation of CD4+CD25+ Treg cells. These results supported the notion that targeted CTLA-4 engagement could result in a selective expansion of Treg cells that can mediate persistent hyporesponsiveness to specific self antigens. Recently, Similar protective effects against Hashimoto's thyroiditis and type-1 diabetes have been noted using antigen-pulsed DCs coated with a CD11c (a dendritic cell surface marker) and CTLA-4 specific BsAb. Therefore, targeted engagement of CTLA-4 on activated T cells could provide an effective means of suppressing autoimmunity in NOD mouse model of type-1 diabetes. Based on these observations, the Company hypothesizes that "Engagement of CTLA-4 concomitant with Ag-specific T-Cell Receptor (TCR) ligation can be used to down modulate pathogenic self reactive T effector cell ("Teff") responses, while inducing Tregs that can suppress Teff function as a means of targeted therapy to: i) prevent the development of T1D; and, ii) stabilize or ameliorate ongoing T1D." To test this hypothesis, Tolerogenics will develop a BsAb that can selectively target mouse beta cells through GLUT2 and down modulate beta cell infiltrating T cells through targeted CTLA-4 engagement in non-obese diabetic (NOD) mice that spontaneously develop type-1 diabetes. Aim-1. Construction and characterization of BsAb to mouse GLUT2 and CTLA-4. Aim-2. To test the ability of anti-mouse GLUT2-anti-CTLA-4 BsAb to suppress T1D. Generation of BsAb that can be used to specifically suppress, stabilize or reverse type-1 diabetes will have significant clinical implications for developing novel therapies for type-1 diabetes in humans. PUBLIC HEALTH RELEVANCE: Autoimmune disease is the third major category of illnesses plaguing the United States and the most common of these diseases affect more than 8.5 million Americans. The burden of immune-mediated diseases is staggering. In the US alone, these conditions result in direct and indirect costs that exceed $100 billion. Existing clinical approaches to autoimmune disorders have relied on the administration of immunosuppressive drugs that result in suppressing the entire immune system. Such a response makes a patient susceptible to a wide range of infectious agents. In Tolerogenics' application, the company proposes to test specific therapeutic approaches aimed at restoring immune regulation and down regulating only the aberrant immune responses using a proprietary bispecific antibody for the treatment of Type I Diabetes, initially. This technology could have major importance not only Type I Diabetes treatment efforts, but for a variety of other autoimmune diseases in the United States including systemic lupus erythematosus (SLE), rheumatoid arthritis, multiple sclerosis, Grave's thyroid disease, Hashimoto's thyroiditis, and others.