CD8 T cell mediated disruption of Blood Brain Barrier Tight Junctions

摘要 恶性疟原虫感染最严重的临床并发症是脑型疟疾(CM)，它有 尽管接受了治疗，但发病率仍然很高。疟疾的传播正变得越来越严重，就像疟疾一样 恶性疟原虫对治疗这种疾病的传统药物产生抗药性。基于上述原因， 了解CM的病因对于治疗这一非常重要的全球性问题至关重要。最近，更严格了 已经对CM患者进行了大规模的MRI研究。正如先前假设的那样， 血脑屏障(BBB)、广泛的水肿和脑肿胀与致死性人类CM有关。给定 以上在人类CM中的观察，血脑屏障破坏和血管通透性的机制需要 已定义。伯氏疟原虫(PBA)感染小鼠是一种已建立的人类CM模型。 与PBA感染相关的相当大的中枢神经系统病理是由急性CD8 T细胞反应驱动的 诱导血脑屏障紧密连接蛋白和中枢神经系统血管通透性的破坏。使用我们的新MHC I类 在条件性基因敲除小鼠中，我们已经确定巨噬细胞和树突状细胞质地不等同 CD8T细胞对PBA感染的反应。而两种抗原提呈细胞都激活了CD8 T细胞 只有树突状细胞上调的CD8T细胞才能产生致命性血脑屏障 颠覆。我们的中心假设是特定的APC亚群，即巨噬细胞、小胶质细胞和 树突状细胞，有助于产生不同的脑内浸润性CD8 T细胞应答PBA 感染。这些不同的CD8 T细胞反应具有不同的能力，可以诱导致命的血脑屏障破坏。 我们计划通过执行以下具体目标来检验这一中心假设： 特定目标#1-确定LysM和CD11c APC产生的大脑浸润性CD8 T细胞谱系 在急性PBA感染期间。 特定目标2-确定CD8T细胞介导的BBB破坏所需的CD11c APC。 特定目标#3-确定由不同抗原启动的CD8 T细胞群的能力 在PBA感染的效应阶段，呈现造成血脑屏障破坏的细胞类型。 这项拟议的工作具有创新性，因为它利用了我们独特的转基因小鼠模型，即新颖的成像 方法，以及我们在梅奥诊所的研究计划可用的新核心设施。我们的目标是定义 炎症在实验性人CM血脑屏障破坏中的作用 使用领先的实验模型获得的知识。除了采用的创新方法外， 抗原提呈细胞提高差异性CD8 T细胞反应的概念是一项非常新的发现 有理由对一种治疗靶向的机制进行进一步研究。在以下情况下，这一点尤其重要 体内CD8 T细胞启动的一种形式是引发致命的神经疾病。

ABSTRACT The most severe clinical complication of Plasmodium falciparum infection is cerebral malaria (CM) which has high morbidity despite treatment. The spread of malaria is becoming increasingly more serious as Plasmodium falciparum develops resistance to traditional drugs used to treat the condition. For the above reasons, understanding the etiology of CM is critical to treat this highly significant global issue. Recently, more rigorous large scale MRI studies have been conducted on CM patients. As previously hypothesized, disruption of the blood-brain barrier (BBB), extensive edema, and brain swelling are associated with fatal human CM. Given the above observations in human CM, the mechanism of BBB disruption and vascular permeability needs to be defined. Plasmodium berghei ANKA (PbA) infection of mice is an established model of human CM. Considerable CNS pathology associated with PbA infection is driven by an acute CD8 T cell response which induces disruption of BBB tight junction proteins and CNS vascular permeability. Using our novel MHC class I conditional knockout mice, we have determined that macrophages and dendritic cells prime non-equivalent CD8 T cell responses in response to PbA infection. While both antigen presenting cells prime CD8 T cell response that infiltrate the brain, only CD8 T cells raised by dendritic cells induce lethal blood-brain barrier disruption. Our central hypothesis is that specific APC subsets, namely macrophages, microglia, and dendritic cells, contribute to the generation distinct brain infiltrating CD8 T cell responses against PbA infection. These distinct CD8 T cell responses have differential ability to induce fatal BBB disruption. We plan to test this central hypothesis through execution of the following specific aims: Specific Aim #1 – Define the brain infiltrating CD8 T cell repertoire raised by LysM+ and CD11c+ APCs during acute PbA infection. Specific Aim #2 – Identify the CD11c+ APC required for CD8 T cell mediated BBB disruption. Specific Aim #3 – Determine the capacity of CD8 T cell populations primed by distinct antigen presenting cell types to inflict BBB disruption during the effector phase of PbA infection. The proposed work is innovative because it capitalizes on our unique transgenic mouse models, novel imaging methodology, and new core facilities available to our research program at Mayo Clinic. Our goal is to define mechanistically the contribution of inflammation to BBB disruption in experimental human CM through knowledge gained using a leading experimental model. Beyond the innovative methodology employed, the concept that antigen presenting cells raise differential CD8 T cell responses is a highly novel finding which warrants further investigation to a mechanism which is therapeutically targetable. This is especially important if one form of CD8 T cell priming in vivo is initiating lethal neurological disease.