Validation of a Negative Regulator as a Novel Therapy for Autoimmune Disease

描述(由申请人提供)：免疫系统依赖于积极和消极信号之间的微妙平衡来维持正常的功能。然而，这种平衡的破坏可能会导致不适当的反应：例如，失去负调控可能会导致自身免疫。VistA(V区免疫球蛋白抑制T细胞活化)，是新近发现的一种免疫功能的负检查点调节因子。在多种癌症模型中的研究表明，阻断Vista依赖信号可以增强肿瘤免疫力。此外，在实验性变态反应性脑脊髓炎(EAE)模型中，阻断Vista可提前发病并增加病情严重程度。这些发现表明，VistA的表达是免疫的重要调节因素，调节这一途径可能会导致治疗自身免疫的新疗法的发展。仅在美国就有近5000万人患有自身免疫性疾病，治疗成本预计将超过1000亿美元/年，开发安全、有效的治疗方法是当务之急。 Vista已经被证实是小鼠系统中的负调控因子。这项提案的目的是确认Vista也是人体免疫的负面调节器。研究将确定Vista在淋巴细胞和髓系群体上的表达。功能研究将确定Vista依赖信号对T细胞增殖、效应器功能和分化的影响。这些研究还将评估Vista是否可能调节其他免疫细胞的功能，为调节Vista途径的疗法提供有价值的见解，可能具有最大的治疗潜力。 不溶形式的Vista-Ig已被证明在体内抑制T细胞反应。这些结果表明，目前尚未确定的受体的参与导致了免疫调节。我们将开发Vista-Ig的多聚体可溶性形式作为潜在的治疗药物。我们将在体外测试它们调节T细胞反应的能力。 针对Vista途径的激动剂可用于治疗各种人类自身免疫性疾病，包括系统性红斑狼疮和多发性硬化症。由于迫切的未得到满足的需求，Vista在EAE中的有据可查的活动，以及我们在MS药物开发方面的经验，我们选择MS作为开发的第一个适应症。 在达到第一阶段STTR的成功标准后，第二阶段STTR计划将开发主要的Vista激动剂作为治疗复发/缓解多发性硬化症的免疫抑制药物。

DESCRIPTION (provided by applicant): The immune system depends upon an exquisite balance between positive and negative signals to maintain proper function. However, disruptions of this balance can lead to inappropriate responses: for example loss of negative regulation can result in autoimmunity. VISTA (V-region Immunoglobulin-containing Suppressor of T cell Activation), is a recently identified negative checkpoint regulator of immune function. Studies in multiple cancer models have shown that blockade of VISTA dependent signals leads to enhanced tumor immunity. Additionally, in a model of experimental allergic encephalomyelitis (EAE), blockade of VISTA resulted in early disease onset and enhanced severity. These findings suggest that VISTA expression is an important regulator of immunity and modulation of this pathway could lead to the development of novel therapeutics for the treatment of autoimmunity. With nearly 50 million people suffering from autoimmune diseases in the US alone, and with treatment costs projected to be over $100B/yr, development of safe, effective therapies is an utmost priority. VISTA has been validated as a negative regulator in the murine system. The goal of this proposal is to confirm that VISTA also functions as negative regulator of human immunity. Studies will determine VISTA expression on both lymphocyte and myeloid populations. Functional studies will determine the effects of VISTA dependent signals on T cell proliferation, effector function and differentiation. The studies also will evaluate whether VISTA may regulate the function of other immune cells providing valuable insights on where therapies modulating the VISTA pathway may have the greatest therapeutic potential. Insoluble forms of VISTA-Ig have been shown to inhibit T cell responses in vivo. These results demonstrate that engagement of the currently undefined receptor leads to modulation of immunity. We will develop multimeric soluble forms of VISTA-Ig as potential therapeutic agents. We will test them in vitro for the ability to modulate T cell responses. Agonists targeted to the VISTA pathway could be used to treat a variety of human autoimmune diseases, including systemic lupus erythematosus and multiple sclerosis. Because of the compelling unmet need, the documented activity of VISTA in EAE, and our experience in the development of drugs in MS, we chose MS as the first indication to develop. After meeting the success criteria for this Phase 1 STTR, the Phase 2 STTR program will develop the lead VISTA agonist as an immunosuppressive drug to treat relapsing/remitting MS.