Evolution of CD8+ TCR affinity during chronic viral infection

描述（由申请方提供）：CD 8 + T细胞是控制病毒感染的重要适应性免疫应答的关键组分。T细胞受体对抗原的亲和力触发CD 8 + T细胞的活化并驱动抗病毒应答的程度。尽管亲和力在T细胞活化中起关键作用，但我们仍然对抗原识别的动态知之甚少，因为免疫应答从初始触发阶段发展到记忆，亲和力的广度和亲和力的潜在变化。此外，我们缺乏关于急性感染期间T细胞亲和力差异的数据，急性感染引起有效的免疫应答，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个问题的令人信服的理由。为了实现这些目标，我们建议使用微量移液管粘附试验来严格定义急性，慢性和表位丢失病毒感染期间二维（2D）CD 8 + T细胞亲和力的宽度。最近的工作强调了2D动力学测量对于准确了解T细胞和APC相互作用的重要性。虽然我们的建议是集中在LCMV动物模型，以证明概念的证明和定义的亲和力的作用，该技术可以很容易地转移到患者样本，以评估T细胞亲和力和CD 8 + T细胞前体频率在慢性感染，如HIV和HCV的肽抗原和HLA限制性分子已被确定。拟议的实验将增加我们对慢性免疫反应期间T细胞生物学的了解，并适用于T细胞参与病理的任何情况。为了测试所述 关于CD 8+抗病毒T细胞应答的广度的假设，我们提出了以下三个具体目标：目标1-确定经历急性或慢性病毒感染的CD 8 + T细胞的亲和力谱。目的2-定义由病毒逃逸突变体攻击的CD 8 + T细胞的亲和力概况和适应性降低的参数。目的3-表征治疗干预后CD 8 + T细胞的亲和力谱。 公共卫生相关性：CD 8 + T细胞在抗病毒免疫反应中发挥重要作用。这项资助的总体目标是确定多克隆T细胞亲和力的范围， 急性和慢性感染期间的病毒抗原。拟议的研究应用了一种新的方法来评估LCMV动物模型的亲和力，但我们的结果应该同样适用于人类慢性感染，如HIV和HCV。因此，我们的发现与人类健康高度相关，并将被证明是评估疾病预后和开发有效治疗方法的宝贵资产。

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. PUBLIC HEALTH RELEVANCE: CD8+ T cells play a major role in the anti-viral immune response. The overall goal of this grant is to define the range of polyclonal T cell affinities for viral antigens during acute and chronic infections. The proposed studies apply a novel means for assessing affinity to the LCMV animal model, but our results should be equally translatable to human chronic infections such as HIV and HCV. Therefore, our findings are highly relevant to human health and will prove to be a valuable asset for assessing disease prognosis and for the development of effective treatments.