A Novel Intervention Strategy for Stroke with RTL Therapy

描述（由申请人提供）：人类中风导致多器官全身性疾病，而不仅仅是脑部病变。虽然患者可能在最初的脑损伤中存活，但许多人死于中枢神经系统损伤引起的免疫抑制和致命的感染。通过脑卒中小鼠大脑中动脉闭塞（MCAO）模型，我们发现脑缺血损伤导致免疫系统的双阶段后果：外周免疫系统的早期全身性激活，包括炎性髓磷脂反应性T细胞，随后是与大量进行性脾细胞凋亡和剩余免疫细胞的丢失或重新分布相关的延迟免疫病理阶段。虽然这第二阶段可能不会直接影响梗死面积，但免疫能力细胞的衰竭会导致无法对抗原挑战做出反应。我们的总体假设是外周T淋巴细胞是缺血后脑损伤和系统性免疫病理发展的主要贡献者。如果是这样的话，能够阻断早期免疫系统激活和调节大脑抗原特异性免疫细胞的治疗将对中风幸存者非常有益。为了解决这一假设，我们将利用我们新开发的“设计师”重组T细胞受体配体（RTL）平台技术来选择性地调节单个髓磷脂反应性T细胞特异性的炎症功能。为了验证这一假设，我们提出：1)确定RTL551对脑抗原致敏T细胞炎症活性的调节是否会减少淋巴细胞对脑的浸润，并改善雌雄动物MCAO后的预后。里程碑：RTL551在两性中都具有保护作用，并且在MCAO后抑制GFP+ T细胞向大脑的易位；2)观察RTL551是否改善了雌雄小鼠MCAO后的外周免疫功能障碍。里程碑：RTL551可改善MCAO后脾细胞数量，抑制细胞因子诱导的脾细胞凋亡和免疫抑制；3)在人源化DR2转基因小鼠中建立脑卒中治疗模型，评估RTL1000（一种HLA-DR2/MOG-35-55构建体，目前正在多发性硬化症患者的I期安全性研究中进行测试）的治疗效果和对MHC和髓磷脂特异性的要求。里程碑：RTL1000将治疗MCAO并预防DR2 Tg小鼠的免疫抑制。如果RTL方法在小鼠中风中有效，则可以迅速应用于人类中风患者。我们的MS RTL构建物RTL1000由hMOG- 35-55肽连接的HLA-DR2片段组成，目前正在FDA批准的I期安全性研究中。如果I期试验表明RTL1000是安全的，那么RTL1000将很快在DR2+中风患者中进行测试。公共卫生相关性：人类中风可导致多器官全身性疾病，而不仅仅是脑部病变。虽然患者可能在最初的脑损伤中幸存下来，但许多人死于中风引起的免疫抑制，这是由免疫系统最初的过度反应引起的。我们寻求开发一种中风疗法，可以阻止初始免疫系统的过度激活，从而对中风幸存者非常有益。

DESCRIPTION (provided by applicant): Human stroke results in multi-organ systemic disease, rather than in solely a brain lesion. While patients may survive the initial brain insult, many succumb to CNS injury-induced immunodepression and fatal infection. Using a murine middle cerebral artery occlusion (MCAO) model of stroke, we found that cerebral ischemic injury leads to bi-phasic consequences for the immune system: early systemic activation of the peripheral immune system, including inflammatory myelin-reactive T cells, followed by a delayed phase of immunopathology associated with massive and progressive splenic apoptosis and loss or re-distribution of remaining immune cells. While this second phase may not directly influence infarct size, exhaustion of immunocompetent cells results in an inability to respond to antigenic challenges. Our overall hypothesis is that peripheral T lymphocytes are major contributors to brain damage after ischemia and to the systemic immunopathology that evolves in tandem. If so, therapy that can block early immune system activation and modulate immunocytes specific for brain antigens would be highly beneficial to stroke survivors. To address this hypothesis, we will utilize our newly developed "designer" recombinant T cell receptor ligand (RTL) platform technology to selectively modulate the inflammatory function of individual myelin-reactive T cell specificities. To test this hypothesis, we propose to 1) determine if RTL551 modulation of the inflammatory activity of brain antigen sensitized T cells results in reduced lymphocyte infiltration into brain and improved outcomes after MCAO in animals of both sexes. Milestone: RTL551 is protective in both sexes and inhibits translocation of GFP+ T cells into brain after MCAO; 2) determine if RTL551 improves peripheral immune dysfunction after MCAO in male and female mice. Milestone: RTL551 will improve splenocyte numbers and suppress cytokine-induced splenic apoptosis and immunosuppression after MCAO; and 3) develop a stroke treatment model in humanized DR2 transgenic mice and evaluate treatment effects and requirements for MHC and myelin specificity of RTL1000, an HLA-DR2/MOG-35-55 construct currently being tested in Phase I safety studies in patients with multiple sclerosis. Milestone: RTL1000 will treat MCAO and prevent immunosuppression in DR2 Tg mice. If effective in murine stroke, the RTL approach could be applied rapidly to human stroke patients. Our RTL construct for MS, RTL1000, is comprised of the HLA-DR2 moiety linked to the hMOG- 35-55 peptide, and currently is in FDA approved Phase I safety studies. The RTL1000 could be tested in DR2+ stroke patients relatively soon if the Phase I trial shows this construct to be safe. PUBLIC HEALTH RELEVANCE: Human stroke results in multi-organ systemic disease, rather than in solely a brain lesion. While patients may survive the initial brain insult, many succumb to stroke induced immunodepression caused by an initial over reaction of the immune system. We seek to develop a stroke therapy that would block the initial immune system over activation and thus be highly beneficial to stroke survivors.