The Role for NKAP in iNKT cell development

描述（由申请人提供）：NKT细胞是一种独特的先天淋巴细胞谱系，表达有限多样性的α-T细胞受体，并识别MHC样CD1d分子上呈递的糖脂抗原。NKT细胞的一个亚群在小鼠中表达不变的TCR 1链Va14-Ja18，因此被命名为iNKT（"不变的NKT细胞"）。NKT细胞对抗原刺激反应迅速，在数分钟或数小时内产生大量细胞因子和趋化因子，调节免疫反应。除了在α-变形菌亚群的清除中具有重要作用之外，iNKT细胞还显示出调节肿瘤监视和肿瘤排斥、自身免疫性疾病和移植物抗宿主病（GVHD）。由于其抗肿瘤作用，正在进行临床试验以动员和激活iNKT细胞对抗癌症。iNKT细胞通过与"常规" aT细胞不同的途径发育，尽管它们共享CD4 + CD8+（DP）胸腺细胞作为共同的前体。我们最近克隆了一个新的转录抑制因子，NKAP，从遗传互补筛选。以前，我们证明了NKAP在T细胞发育的早期是必需的，因为使用Lck-cre转基因的NKAP的条件性缺失会导致T细胞发育的早期阻滞，但会离开？d T细胞发育不受影响。为了理解NKAP在T细胞发育后期的功能，我们产生了CD4-cre NKAP cKO小鼠，其在胸腺细胞发育的DP阶段有效地删除NKAP。DP T细胞中NKAP表达的丧失导致iNKT细胞发育的完全废除，而常规aT细胞发育不受影响。iNKT细胞生成中的这种缺陷不是由于DP T细胞中缺乏CD1d表达，也不是由于它们表达对iNKT细胞发育至关重要的两种Slam家族受体Slamf1（也称为CD150）和Slamf6（也称为Ly108）。在本提案中，我们将定义在不存在NKAP的情况下iNKT细胞发育失败的分子原因。

DESCRIPTION (provided by applicant): NKT cells are a unique innate lineage of lymphocytes which express a¿ T cell receptors of limited diversity and recognize glycolipid antigens presented on MHC-like CD1d molecules. A subset of NKT cells express an invariant TCR1 chain, Va14-Ja18 in mice, and are thus named iNKT ("invariant NKT cells"). NKT cells respond quickly to antigenic stimulation, producing significant quantities of cytokines and chemokines within minutes or hours, which regulate the immune response. In addition to having an important role in the clearance of a subset of alpha-proteobacteria, iNKT cells have also been shown to regulate tumor surveillance and tumor rejection, autoimmune diseases, and graft versus host disease (GVHD). Because of their anti-tumor effects, clinical trials are underway to mobilize and activate iNKT cells in fighting cancer. iNKT cells develop via a distinct pathway from 'conventional' a¿ T cells, although they share CD4+CD8+ (DP) thymocytes as a common precursor. We have recently cloned a novel transcriptional repressor, NKAP, from a genetic complementation screen. Previously, we demonstrated that NKAP is required early in T cell development, as conditional deletion of NKAP, using an Lck-cre transgene, results in an early block in a¿ T cell development but leaves ?d T cell development unaffected. To understand the function of NKAP later in a¿ T cell development, we generated CD4-cre NKAP cKO mice, which delete NKAP efficiently at the DP stage of thymocyte development. Loss of NKAP expression in DP T cells leads to a complete abrogation of iNKT cell development, while conventional a¿ T cell development is unaffected. This defect in iNKT cell generation is not due to lack of CD1d expression in DP T cells, nor in their expression of two Slam family receptors that are critical to iNKT cell development, Slamf1 (also known as CD150) and Slamf6 (also known as Ly108). In this proposal, we will define the molecular cause(s) for the failure in the development of iNKT cells in the absence of NKAP.