Presentation of Qa-1 restricted peptides during homeostasis and viral infection

项目主任/首席调查员(罗比，艾伦，A)： 摘要： 小鼠Qa-1是非经典MHC-1分子(MHC1b)中保守的MHC-E家族成员。在……里面 大多数细胞，MHC-E提供源自经典(MHC1a)分子的前导序列的肽，以及 通过胚系编码受体CD94/NKG2调节NK细胞的功能。MHC-E分子可以 也将自身和病原体衍生的多肽呈递给CD8T细胞。这些信号导致了 MHC-E的替代多肽，以及应答的CD8T细胞的功能仍然知之甚少。 最近，一种基于CMV载体的高效HIV疫苗的研究揭示了一种突出的MHC-E 限制CD8 T细胞反应，提高了对其呈递机制和体内研究的新兴趣 MHC-E的功能。 与我们的合作者一起，我们一直在研究Qa-1限制的T细胞对细胞的反应 缺乏与抗原处理相关的ER氨基肽酶(ERAAP Ko)(Nagarajan等人，2012年)。这个 反应性CD8 T细胞识别来自自身蛋白(FAM49的Fl9)的9聚体多肽 Qa-1(B)(称为QFL T细胞)。QFL T细胞使用不变的TCRa，并具有两者的特征 常规和非常规CD8T细胞。我们的初步数据表明，QFL T细胞遇到了高水平 稳定状态和病毒感染期间的亲和力Qa-1限制性配体。我们建议使用新生成的 TCR转基因小鼠体内产生QFL T细胞Qa-1限制性配体的研究 稳定状态和病毒感染期间。在目标1中，我们将确定pMHC配体参与的阳性和 QFL T细胞激动剂的选择，并将识别呈现配体的胸腺细胞类型。在目标2中，我们将 确定驱动QFL T细胞内稳态扩张的配体(S)，并将决定何时、在什么情况下 组织，以及它们由什么细胞类型(S)呈现。在目标3中，我们将确定导致 在MCMV感染期间QFL T细胞的启动，并将测试在MCMV期间是否诱导QFL T细胞 感染可以杀死受感染的细胞，并提供免疫保护。 我们的结果将为MHC-E如何调节T细胞反应提供新的线索，具有重要的意义 对疫苗设计的影响。 OMB编号0925-0001/0002(01/18修订版批准至2020年3月31日)页面续格式页面

Program Director/Principal Investigator (Robey, Ellen, A): Abstract: Mouse Qa-1 is a member of the conserved MHC-E family of non-classical MHC-1 molecules (MHC1b). In most cells, MHC-E presents peptides derived from the leader sequences of classical (MHC1a) molecules, and regulates the function of NK cells through the germ-line encoded receptor CD94/NKG2. MHC-E molecules can also present self and pathogen-derived peptides to CD8 T cells. The signals that lead to presentation of alternative peptides by MHC-E, and the functions of the responding CD8 T cells remain poorly understood. Recently, studies of a highly effective HIV vaccine based on a CMV vector revealed a prominent MHC-E restricted CD8 T cell response, raising new interest in understanding the presentation mechanisms and in vivo functions of MHC-E. Together with our collaborators, we have been investigating a Qa-1-restricted T cell response to cells lacking the ER aminopeptidase associated with antigen processing (ERAAP ko) (Nagarajan et al., 2012). The responding CD8 T cells recognize a 9-mer peptide derived from a self-protein (FL9 from FAM49) presented by Qa-1(b) (called QFL T cells). QFL T cells use an invariant TCR a, and have characteristics of both conventional and non-conventional CD8 T cells. Our preliminary data indicate that QFL T cells encounter high affinity Qa-1 restricted ligands at steady state and during viral infection. We propose to use a newly generated TCR transgenic mouse strain to probe the in vivo generation of Qa-1 restricted ligands for QFL T cells in both steady state and during viral infection. In Aim 1, we will identify the pMHC ligands involved in positive and agonist selection of QFL T cells, and will identify the thymic cell types that present the ligands. In Aim 2, we will identify the ligand(s) that drive the homeostatic expansion of QFL T cells, and will determine when, in what tissue, and by what cell type(s) they are presented. In Aim 3, we will determine the mechanisms that lead to priming of QFL T cells during MCMV infection, and will test whether QFL T cells induced during MCMV infection can kill infected cells and provide immune protection. Our results will shed new light on how MHC-E presentation regulates T cell responses, with important implications for vaccine design. OMB No. 0925-0001/0002 (Rev. 01/18 Approved Through 03/31/2020) Page Continuation Format Page