Evolution of CD8+ TCR affinity during chronic viral infection

描述(由申请人提供)：CD8+T细胞是适应性免疫反应的关键组成部分，对控制病毒感染非常重要。T细胞受体与抗原的亲和力触发CD8+T细胞的激活，并驱动抗病毒反应的程度。尽管亲和力在T细胞激活中起着关键作用，但我们仍然对抗原识别的动力学知之甚少，包括亲和力的广度和随着免疫反应从最初的触发阶段演变到记忆过程中亲和力的潜在变化。此外，我们缺乏关于在急性感染和慢性感染期间T细胞亲和力的差异的数据，这些T细胞亲和力可以引发有效的免疫反应，而慢性感染则证明细胞免疫无效。TCR亲和力对抗原识别的重要性和我们缺乏知识是研究这一问题的有力理由。为了实现这些目标，我们建议使用微管黏附试验来严格定义急性、慢性和表位缺失病毒感染期间CD8+T细胞在二维(2D)的亲和力的广度。最近的工作强调了2D动力学测量的重要性，以获得T细胞和APC相互作用的准确视图。虽然我们的建议集中在LCMV动物模型上，以证明概念并确定亲和力的作用，但该技术可以很容易地转移到患者样本，以评估慢性感染期间的T细胞亲和力和CD8+T细胞前体频率，如已识别多肽抗原和HLA限制分子的艾滋病毒和丙型肝炎病毒。拟议的实验将增加我们在慢性免疫反应期间的T细胞生物学知识，适用于T细胞参与病理的任何情况。为了测试所述的 对于CD8+抗病毒T细胞反应的广度假设，我们提出了以下三个具体目标：目的1-确定CD8+T细胞在急性或慢性病毒感染中的亲和力。目的2-确定病毒逃逸突变体攻击的CD8+T细胞的亲和力分布和适应性降低的参数。目的3-研究治疗干预后CD8+T细胞的亲和力变化。

DESCRIPTION (provided by applicant): CD8+ T cells are critical components of the adaptive immune response important for controlling viral infections. The affinity of T cell receptor for antigen triggers the activation of CD8+ T cells and drives the extent of the anti-viral response. Despite the key role of affinity in T cell activation, we still know quite little about the dynamic of antigen recognition in terms of the breadth of affinities and potential changes in affinity as the immune response evolves from initial triggering stage through memory. In addition, we lack data on differences in T cell affinities during acute infections, which elicit effective immune responses, and chronic infections where cellular immunity proves ineffective. The importance of TCR affinity for antigen recognition and our lack of knowledge are compelling reasons to investigate this issue. Toward these goals, we propose to use the micropipette adhesion assay to rigorously define the breadth of CD8+ T cell affinities in 2 dimensions (2D) during acute, chronic, and epitope loss viral infections. Recent work has highlighted the importance of 2D kinetic measurements to obtain an accurate view of T cell and APC interactions. While our proposal is focused toward the LCMV animal model to demonstrate proof of concept and define the role of affinity, the techniques could be readily transferred to patient samples to assess T cell affinity and CD8+ T cell precursor frequency during chronic infections such as HIV and HCV for which peptide antigens and HLA restriction molecules have been identified. The proposed experiments will increase our knowledge of T cell biology during chronic immune responses, with application to any situation in which T cells participate in the pathology. To test the stated hypotheses as to the breadth of the CD8+ anti-viral T cell response, we propose the following three specific aims: Aim 1- Determine the affinity profile of CD8+ T cells undergoing acute or chronic viral infections. Aim 2- Define the affinity profile and the parameters of diminished fitness of CD8+ T cells challenged by viral escape mutants. Aim 3- Characterize the affinity profile of CD8+ T cells after therapeutic interventions.