Structural Immunology of CD1 and CD1-TCR Complexes

描述（由申请人提供）：在过去的10年里，积累了大量的数据，证明了糖脂反应性T细胞在自身免疫性疾病、宿主防御和肿瘤发展中的作用。T细胞和NKT细胞可以对CD1分子呈递的大量自身和外来抗原作出反应，并可以通过细胞毒性T淋巴细胞（ctl）触发杀死抗原呈递细胞，或通过产生可溶性抗体从体液免疫系统获得帮助（T辅助细胞）。我们的实验室对细胞介导免疫中脂质抗原识别的分子机制感兴趣。为了实现这一目标，我们通过表面等离子体共振研究（SPR）确定了各种糖脂反应性T细胞受体（TCR）与各种CD1抗原呈递分子的结合动力学。我们将进一步将获得的结果与使用T细胞杂交瘤测量T细胞活化时细胞因子产生的数据联系起来。最后，我们建议用x射线晶体学来确定CD1抗原受体与不同脂质和同源T细胞受体（TCR's）复合物的三维结构。我们具体解决以下具体目标：1)人类和小鼠硫脂反应性NKT细胞的生化和功能特性。我们将通过各自的TCR确定载硫脂的人CD1a和小鼠CD1d复合物的结构，并通过SPR表征它们的结合动力学。这两种复合物的比较将提供免疫系统对硫脂识别的相似性和差异性的见解，并将阐明其激活的分子机制。2)我们将从结构和功能上表征人和小鼠NKT细胞对伯氏疏螺旋体糖脂识别的差异。3)我们将描述新型内源性自脂与小鼠CD1d的结合及其在NKT细胞中的识别。对自身抗原和微生物抗原呈递差异的结构洞察将有助于理解微生物脂质和脂质反应性T细胞在宿主防御和自身免疫性疾病中的作用。公共卫生相关性：NKT细胞是由几种亚型组成的特化淋巴细胞，在多发性硬化症等自身免疫性疾病的过程中，可以对感染性生物（如莱姆病的病原体伯氏疏螺旋体）和自身脂质产生反应。在分子水平上了解这些细胞类型的功能特性对于未来开发新的化疗药物或佐剂来对抗这两种疾病至关重要。

DESCRIPTION (provided by applicant): Over the past 10 years, a tremendous amount of data has accumulated, which demonstrates the role of glycolipid-reactive T cells in autoimmune disease, host defense and tumor development. T cells and NKT cells can respond to a broad pool of self and foreign antigens presented by CD1 molecules and can trigger killing of the antigen presenting cell, through cytotoxic T lymphocytes (CTLs), or recruit help (T helper cells) from the humoral immune system through production of soluble antibodies. Our lab is interested in the molecular mechanisms of lipid antigen recognition in cell-mediated immunity. Toward this goal, we determine the binding kinetics of various glycolipid- reactive T cell receptor's (TCR's) with various CD1 antigen-presenting molecules by surface plasmon resonance studies (SPR). We will further correlate the obtained results with data obtained by measuring cytokine production upon T cell activation using T cell hybridomas. Ultimately we propose to determine the three-dimensional structure of CD1 antigen receptors in complex with different lipids and cognate T cell receptors (TCR's) by x-ray crystallography. We specifically address the following specific aims: 1) What are the biochemical and functional properties of human and mouse sulfatide-reactive NKT cells. We will determine the structure of sulfatide loaded human CD1a and mouse CD1d in complex with the respective TCR and characterize their binding kinetics by SPR. Comparisons of both complexes will provide insights into the similarities and disparities of sulfatide recognition by the immune system and will shed light on the molecular mechanism of their activation. 2) We will structurally and functionally characterize differences in glycolipid recognition of Borrelia burgdorferi glycolipids by human and mouse NKT cells. 3) We will characterize binding of novel endogenous self-lipids to mouse CD1d and their recognition by NKT cells. Structural insights into the differences of self vs. microbial antigen presentation will help understand the role of microbial lipids and lipid-reactive T cells in host defense and autoimmune diseases. Public Health Relevance: NKT cells are specialized lymphocytes that consist of several subtypes and can respond to glycolipids from infectious organisms, such as Borrelia burgdorferi the causative agent of Lyme disease and self-lipids, during the course of autoimmune disease such as Multiple sclerosis. Understanding the functional properties of these cell types at a molecular level is crucial for the future development of novel chemotherapeutic agents or adjuvants to combat both diseases.