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

描述（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优先向先天CD94/NKG2受体提供基本不变的经典Ia类蛋白信号肽（HLA-A、-B和-C），从而调节NK细胞活性。hla - e限制性调节性CD8+ T细胞可预防自身免疫。有趣的是，在某些细菌和病毒感染时，HLA-E显示出非常多样化的病原体衍生肽库，这些肽可被CD8+ T细胞的TCR感知。我们报道了第一个hla - e限制性HIV Gag表位（KL9），使用体外再刺激的CD8+ T细胞从精英控制者中鉴定。hla - e限制性kl9特异性T细胞的功能分析揭示了效应（脱颗粒）和调节功能（IL-26的产生）。这项工作将开始剖析这种尚未定义的宿主免疫，特别是绘制保守的表位，并评估这些反应性在HIV感染中基于HLA-E的抗原递呈系统中的特征。这项工作对艾滋病毒疫苗的开发很重要，因为病毒可能利用这种机制来限制宿主免疫。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艾滋病毒，从而提供一定程度的保护，同时避免过度的炎症和病理，尽管代价是病毒持续存在和慢性感染。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。HLA-E多态性的缺乏进一步表明，与受高度多态性的Ia类位点限制的表位相比，一些HLA-E结合的表位可能是通用HIV疫苗的潜在候选者。Specific Aim 1将利用来自精英控制者的CD8+ T细胞绘制HIV蛋白质组中保守区域的hla - e限制性表位。表位将通过质谱法进行验证。由于HLA-E的tcr结合面基本上是“单态的”，因此，结合的肽强烈影响特异性和功能，因此预计单个HIV表位会引发定性不同的CD8+反应。特异性目标2将检查hla - e限制性CD8+ T细胞的效应和调控功能概况以及公共TCR使用情况。三个T细胞培养将从精英控制者或偶然从健康供体中产生

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. PUBLIC HEALTH RELEVANCE: The United Nations estimated in 2009 that 33 million people worldwide were living with HIV-1 Infection with 2.6 million new infections (http://www.unaids.org/globalreport/documents/20101123_GlobalReport_full_en.pdf). Development of preventative and therapeutic vaccines is crucial to address this significant global health problem. Optimal vaccine development requires insight into the mechanisms of protective responses to HIV. This proposal will study a recently identified new subset of white blood cells (CD8+ T cells) that can affect both spontaneous and acquired immunity to HIV.