Glycolipid Presentation by CD1d

描述（由申请方提供）：自身和微生物糖基神经酰胺作为由CD 1d（一种脂质结合MHC样分子）呈递的NKT细胞抗原发挥重要的免疫功能。这些功能的范围从宿主对病原体的防御到癌症排斥、自身免疫和过敏的调节。此外，合成的糖基神经酰胺可以用作疫苗的佐剂，并且可以通过Th 1或Th 2细胞因子的释放来调节各种疾病状况，包括糖尿病、实验性过敏性脑脊髓炎、狼疮和癌症排斥。其他糖基神经酰胺引发可能参与多发性硬化的适应性T细胞应答。因此，该计划项目使用糖基神经酰胺作为模型抗原家族来研究CD 1d分子的糖脂抗原呈递，具有潜在的临床应用，以及脂质转运和识别中的基本问题。 一个多学科的方法，包括糖脂分析和合成化学，蛋白质表达，生物物理学和结构生物学，以及细胞免疫学和细胞生物学，已经组装，以确定NKT配体从天然来源和研究其免疫生物学的基本方面。在过去的资助期间，在确定关键的自身和微生物NKT细胞抗原，表征其呈递所必需的脂质转移蛋白，阐明其晶体结构和开发一组合成变体以研究其细胞生物学及其在疫苗和免疫调节中的功能影响方面取得了里程碑式的成就。这些方法将追求的目标是发展的脂质摄取，运输和加载的细胞生物学的生物物理和结构方面的结合蛋白质受体，如CD 1d，TCR和其他脂质结合蛋白的基本理解;并在体内整合这方面的知识在NKT细胞介导的免疫反应感染或合成佐剂的功能水平。个别研究项目如下。项目1。萨维奇：微生物NKT配体的鉴定和合成，以及结构变体和缀合物的设计，以了解其功能特性。项目2. Tyton：脂质与CD 1d，TCR和其他脂质结合或转移蛋白相互作用的生物化学，生物物理和结构方面。项目3。Bendelac：与小鼠体内NKT配体识别相关的功能和糖基神经酰胺的细胞内运输特性 项目1：TH 1/TH 2糖脂佐剂（Savage，P） 项目1描述（由申请人提供）：自然杀伤T细胞（NKT细胞）在调节免疫应答中发挥重要作用。NKT细胞由CD 1d呈递的糖脂抗原刺激，在过去的几年中，在理解这一过程方面取得了重大进展。NKT细胞的天然抗原已被鉴定，与糖脂结合的CD 1d的晶体结构已被解决。随着导致NKT细胞刺激的因素的阐明，糖脂运输和与T细胞受体（TCR）的特异性相互作用的重要性正在显现。然而，糖脂运输和与TCR的相互作用还不清楚。拟议的研究包括开发标记糖脂用于研究特定的贩运事件;具体而言，糖脂的结构变化对贩运的影响以及贩运差异如何影响NKT细胞释放细胞因子的Th 1/Th 2偏倚。糖脂和CD 1d与TCR相互作用的研究将涉及已知抗原的增量结构修饰，以确定缔合和刺激的要求。此外，糖脂功能已被鉴定为可以被修饰而不会对NKT细胞刺激产生负面影响，并且该信息提供了一种使用附加到糖脂上的小分子来修饰TCR对糖脂-CD 1d复合物的亲和力的方法。预计较高的亲和力将导致NKT细胞刺激延长和细胞因子释放增加;然而，该亲和力对细胞因子释放特征的影响尚不清楚，这些研究将提供该信息。产生NKT细胞天然抗原的已知生物体的数量相当少，并且将针对NKT刺激行为筛选与已知直接刺激NKT细胞的生物体相关的细菌。然后通过全合成确定和确认抗原的结构。 与公共卫生的相关性：NKT细胞的反应影响疾病状态，包括感染，肿瘤排斥和自身免疫性疾病。了解糖脂如何刺激NKT细胞的不同反应将有助于利用这些反应来改善人类健康。拟议的研究将增加这种理解，同时增加刺激NKT细胞的糖脂库。

DESCRIPTION (provided by applicant): Self and microbial glycosylceramides perform important immunological functions as NKT cell antigens presented by CD1d, a lipid-binding MHC-like molecule. These functions range from host defense against pathogens to the regulation of cancer rejection, autoimmunity and allergy. Further, synthetic glycosylceramides can be used as adjuvants of vaccines and can modulate, through the release of either Thl or Th2 cytokines, various disease conditions including diabetes, experimental allergic encephalomyelitis, lupus and cancer rejection. Other glycosylceramides elicit adaptive T cell responses that may be involved in Multiple Sclerosis. Thus, the program project uses glycosylceramides as a model antigen family to study glycolipid antigen presentation by CD1d molecules, with potential clinical applications, as well as fundamental issues in lipid transport and recognition. A multidisciplinary approach encompassing glycolipid analytic and synthetic chemistry, protein expression, biophysics and structural biology, as well as cellular immunology and cell biology, has been assembled to identify NKT ligands from natural sources and study fundamental aspects of their immunobiology. The past funding period has produced landmark accomplishments in identifying key self and microbial NKT cell antigens, characterizing lipid transfer proteins essential for their presentation, elucidating their crystal structures and developing a panel of synthetic variants to study their cell biology and their functional impact in vaccine and immunomodulation. These approaches will be pursued with the goal of developing a basic understanding of the cell biology of lipid uptake, trafficking and loading, of the biophysical and structural aspects of their binding to protein receptors such as CD1d, TCR and other lipid binding proteins; and integrating this knowledge in vivo at the functional level during NKT cell mediated immune responses to infection or to synthetic adjuvants. The individual research projects are as follows. Project 1. Savage: Identification and synthesis of microbial NKT ligands and design of structural variants and conjugates to understand their functional properties. Project 2. Teyton: Biochemical, biophysical and structural aspects of lipid interaction with CD1d, TCR and other lipid binding or transfer protein. Project 3. Bendelac: Functions associated with NKT ligand recognition in vivo in mice and intracellular trafficking properties of glycosylceramides PROJECT 1: TH1/TH2 Glycolipid Adjuvants (Savage, P) PROJECT 1 DESCRIPTION (provided by applicant): Natural killer T cells (NKT cells) play an important role in regulating immune responses. NKT cells are stimulated by glycolipid antigens presented by CD1d, and in the last few years significant advances have been made in understanding this process. Natural antigens for NKT cells have been identified, and crystal structures of CD1d bound to glycolipids have been solved. As factors leading to NKT cell stimulation are elucidated, the importance of glycolipid trafficking and specific interactions with T cell receptors (TCRs) is emerging. However, glycolipid trafficking and interactions with TCRs are not well understood. Proposed research includes development of labeled glycolipids for use in studying specific trafficking events; specifically, the influences of structural variations of glycolipids on trafficking and how differences in trafficking influence the Th1/Th2 bias of cytokine release by NKT cells. Studies of glycolipid and CD1d interactions with TCRs will involve incremental structural modifications of known antigens to determine requirements for association and stimulation. In addition, glycolipid functionality has bee identified that can be modified without impacting negatively NKT cell stimulation, and this information provides a means of using small molecules appended to glycolipids to modify the affinity of TCRs for glycolipid-CD1d complexes. It is anticipated that higher affinity will result in prolonged stimulation of NKT cells and increased cytokine release; however, the impact of this affinity on cytokine release profiles is not known and these studies will provide that information. The number of known organisms producing natural antigens for NKT cells is rather small, and bacteria related to those known to stimulate NKT cell directly will be screened for NKT stimulatory behavior. Structures of antigens will then be determined and confirmed through total synthesis. Relevance to Public Health: Responses of NKT cells influence disease states including infection, tumor rejection, and autoimmune diseases. An understanding of how glycolipids stimulate different responses from NKT cells will facilitate use of these responses to improve human health. Proposed research will increase this understanding while augmenting the arsenal of glycolipids that stimulate NKT cells.