Effector and Regulatory Activities of HLA-E-restricted HIV-specific abCD8 T Cells

描述（由申请人提供）：HLA-E是一种普遍表达的非经典Ib类分子。在稳态条件下，HLA-E优先将经典Ia类蛋白（HLA-A、-B和-C）的基本不变的信号肽呈递给先天性CD 94/NKG 2受体，从而调节NK细胞活性。HLA-E限制性调节性CD 8 + T细胞可能会预防自身免疫。有趣的是，在某些细菌和病毒感染的情况下，HLA-E显示出由CD 8 + T细胞的TCR感知的病原体衍生肽的显著多样性。我们报告了第一个HLA-E限制性HIV Gag表位（KL 9），该表位是使用来自精英控制者的体外再刺激的CD 8 + T细胞鉴定的。对HLA-E限制性KL 9特异性T细胞的功能分析揭示了效应子（脱粒）和调节功能（IL-26产生）。这项工作将开始解剖这种尚未确定的宿主免疫，特别是绘制保守表位，并评估这些反应性的特点，在HLA-E为基础的抗原呈递系统在HIV感染。这项工作对HIV疫苗的开发很重要，因为病毒可能已经选择了这种机制来限制宿主免疫力。在HLA-E的背景下，效应免疫和调节免疫之间的平衡可能允许部分清除HIV，从而提供一定水平的保护，同时避免过度炎症和病理，尽管以病毒持续存在和慢性感染为代价。了解嵌入的HLA-E限制性表位如何影响HIV免疫的诱导对于疫苗设计至关重要。缺乏HLA-E多态性进一步意味着一些HLA-E结合表位可能是通用HIV疫苗的潜在候选者，与高度多态性Ia类基因座限制的那些相反。Specific Aim 1将使用已建立的方案，利用来自精英控制者的CD 8 + T细胞，在HIV蛋白质组的保守结构域中绘制HLA-E限制性表位。将通过质谱法验证表位。预期单个HIV表位引起定性不同的CD 8+应答，因为HLA-E的TCR结合面基本上是“单态性的”，因此结合的肽强烈影响特异性和功能。特异性目标2将检查效应和调节功能概况以及HLA-E限制性CD 8 + T细胞对新映射特异性的公共TCR使用。三个T细胞培养物将从精英控制者或偶然地从健康供体中产生， 表位作图。对公共TCR的选择可能表明，大部分人群能够响应，并且这些结构可以通过新技术如TCR亲和力成熟来开发，以产生新类别的治疗剂。具体目标3将在30名控制者和40名停止ART的进展患者中进行HLA-E限制性HIV特异性CD 8 + T细胞的相关性研究。这些HLA-E表位与NKG 2受体相互作用的能力也将在10名HIV血清阳性个体中用HLA-E四聚体进行评估。这些研究将为HLA-E限制性NK和CD 8 + T细胞监测在HIV感染中的作用提供见解。

DESCRIPTION (provided by applicant): HLA-E is a ubiquitously expressed non-classical class Ib molecule. Under homeostatic conditions, HLA-E preferentially presents essentially invariant signal peptides of classical class Ia proteins (HLA-A, -B, and -C) to the innate CD94/NKG2 receptors, thereby regulating NK cell activity. HLA-E-restricted regulatory CD8+ T cells may prevent autoimmunity. Of interest, with infections by certain bacteria and viruses, HLA-E displays a remarkably diverse repertoire of pathogen-derived peptides that are sensed by ¿¿ TCR of CD8+ T cells. We report the first HLA-E-restricted HIV Gag epitope (KL9) identified using in vitro-re-stimulated CD8+ T cells from an elite controller. Functional analysis f HLA-E-restricted KL9-specific T cells revealed both effector (degranulation) and regulatory functions (IL-26 production). This work will begin to dissect this yet undefined host immune immunity, particularly to map conserved epitopes and assess the character of these reactivities within the HLA-E based antigen presentation system in HIV infection. This work is important for HIV vaccine development because the virus may have co-opted this mechanism to limit host immunity. A balance between effector and regulatory immunity in the context of HLA-E might allow partial clearance of HIV, thus providing some levels of protection while avoiding excessive inflammation and pathology, albeit at the cost of viral persistence and chronic infection. Understanding how embedded HLA-E-restricted epitopes affect the induction of HIV immunity would be crucial for vaccine design. The lack of HLA-E polymorphism further implies that some HLA-E-bound epitopes may be potential candidates for a universal HIV vaccine, in contrast with those restricted by the highly polymorphic class Ia loci. Specific Aim 1 will map HLA-E-restricted epitopes in conserved domains across the HIV proteome with CD8+ T cells from elite controllers using an established protocol. Epitopes will be verified by mass spectrometry. Individual HIV epitopes are expected to elicit qualitatively distinct CD8+ responses, since the TCR-binding face of HLA-E is basically "monomorphic" and thus, the bound peptide strongly influences specificity and functions. Specific Aim 2 will examine the effector and regulatory functional profiles and public TCR usage of HLA-E-restricted CD8+ T cells to the newly mapped specificities. Three T cell cultures will be generated from elite controllers or contingently from healthy donors for each epitope mapped. Selection of public TCRs may indicate that a large segment of the human population is capable of responding and these structures can be exploited by new technologies such as TCR affinity maturation to create new classes of therapeutic agents. Specific Aim 3 will be a correlative study of HLA-E-restricted HIV-specific CD8+ T cells in 30 controllers and 40 progressor patients who are off ART. The ability of these HLA-E epitopes to interact with NKG2 receptors will also be assessed with HLA-E tetramers in 10 HIV seropositive individuals. These studies will provide insights into the role of HLA-E-restricted NK and CD8+ T cell surveillance in HIV infection.