A novel blood-CSF adaptive immune response in Alzheimer's disease

阿尔茨海默病(AD)是一种无法治愈的神经退行性疾病，越来越多的人认识到神经炎症在其中发挥着关键作用。虽然先天炎症与AD有关，但对获得性免疫反应的作用知之甚少。本申请中的初步数据显示了AD的外周免疫特征，其特征是高度分化的CD8T效应记忆CD45RA(TEMRA)细胞数量增加。值得注意的是，住院患者脑脊液(CSF)中也存在CD8-TEMRA细胞，T细胞受体(TCR)测序显示其克隆性扩增，提示这些适应性免疫细胞具有抗原特异性。TCR克隆和多肽筛选表明，克隆扩增的AD-CSF TCR亚群对EB病毒(EBV)BZLF1抗原具有特异性。这些结果首次提供了克隆的、经历过抗原的T细胞在受年龄相关神经变性影响的脑鞘内巡逻的证据。这个K99/R00应用程序将测试有害适应性免疫反应在AD病理生物学中的作用这一新理论。在特定目的1中，AD血-CSFT细胞克隆型将与脑脊液生物标志物相关。这一方法将确定AD中特定的T细胞群，以及这些细胞是否与疾病严重程度有关。在特定目的2中，将利用抗原鉴定筛选来检测推动AD患者T细胞克隆性增殖的自身/非自身抗原(S)。这些检测可能会发现AD的新治疗靶点或生物标记物。具体目标3将利用诱导神经元(IN)细胞与患者脑脊液CD8 T细胞共培养来确定AD患者中T细胞介导的神经元死亡和恢复的机制。这些实验将评估AD-CSF CD8 T细胞是否对感染EBV的细胞和/或对BZLF1分子模拟物产生细胞毒性效应反应。这位候选人大卫·盖特博士在T细胞生物学方面拥有丰富的经验，并花了十多年的时间研究AD。在该奖项的指导阶段，Gate博士的目标是提高他在下一代测序分析、复杂的统计方法、抗原筛选、培养方法和CRISPR基因编辑方面的知识。盖特博士的导师托尼·怀斯-科雷博士和马克·戴维斯博士分别在这些领域拥有全面的专业知识。他们将为盖茨博士提供一个丰富的环境，使其发展成为神经免疫学研究领域的杰出独立研究员。作为一名独立的研究员，Gate博士将利用这一奖学金下的培训来全面和定量地评估T细胞分子成分与神经退行性变之间的相互作用。

Alzheimer’s disease (AD) is an incurable neurodegenerative disorder in which neuroinflammation is increasingly recognized to play a critical function. While innate inflammation has been implicated in AD, little is known about the contribution of the adaptive immune response. Preliminary data featured in this application demonstrate a peripheral immune signature of AD characterized by increased numbers of highly differentiated CD8+ T effector memory CD45RA+ (TEMRA) cells. Strikingly, CD8+ TEMRA cells were also present in-patient cerebrospinal fluid (CSF) and T cell receptor (TCR) sequencing indicated their clonal expansion, suggesting antigen specificity of these adaptive immune cells. TCR cloning and peptide screens demonstrated specificity of a subset of clonally expanded AD CSF TCRs to the Epstein-Barr virus (EBV) BZLF1 antigen. These results provide the first evidence of clonal, antigen-experienced T cells patrolling the intrathecal space of brains affected by age-related neurodegeneration. This K99/R00 application will test the novel theory of a detrimental adaptive immune response contributing to AD pathobiology. In Specific Aim 1, AD blood-CSF T cell clonotypes will be related to CSF biomarkers. This approach will determine specific T cell populations in AD and whether these cells relate to disease severity. In Specific Aim 2, antigen identification screens will be used to detect the self/non-self-antigen(s) driving T cell clonal expansion in AD. These assays could uncover a novel therapeutic target or biomarker for AD. Specific Aim 3 will determine mechanisms of T cell-mediated neuronal death and resiliency in AD using induced neuronal (iN) cells co-cultured with patient CSF CD8+ T cells. These experiments will assess whether AD CSF CD8+ T cells mount cytotoxic effector responses to iN cells infected with EBV and/or to a molecular mimic of BZLF1. The candidate, Dr. David Gate, has extensive experience in T cell biology and has spent more than a decade studying AD. During the mentoring phase of this award, Dr. Gate aims to advance his knowledge in next-generation sequencing analysis, sophisticated statistical methods, antigen screening, iN culturing methods and CRISPR gene editing. Dr. Gate's mentor and co-mentor, Dr. Tony Wyss-Coray and Dr. Mark Davis, respectively, have comprehensive expertise in these areas. They will provide an enriching environment for Dr. Gate to develop as a prominent independent investigator in neuroimmunology research. As an independent investigator, Dr. Gate will leverage the training under this fellowship to comprehensively and quantitatively evaluate the interactions between T cell molecular components and neurodegeneration.