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Studies of Antigen Stimulation

抗原刺激的研究

基本信息

批准号：
7846477
负责人：
EMIL Raphael UNANUE
金额：
$ 3.74万
依托单位：
WASHINGTON UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2009
资助国家：
美国
起止时间：
2009-06-19 至 2010-09-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7846477
关键词：
Affinity Amino Acids Antigen Presentation Antigen Presentation Pathway Antigen-Presenting Cells Antigens Area Arts Autoimmune Diabetes Autologous Beta Cell Binding Biochemical Biochemistry Biology CD4 Positive T Lymphocytes Cell Line Cell surface Cellular biology Chemicals Chemistry Collaborations Complex Egg White Enzyme-Linked Immunosorbent Assay Epitopes Family Foundations Frequencies Genes Grant High Pressure Liquid Chromatography Histocompatibility Antigens Class II Housing Human Resources Immunology Infection Inflammation Investigation Ions Isomerism Laboratories Length Listeria monocytogenes MHC binding peptide Mass Spectrum Analysis Mediating Modeling Molecular Monoclonal Antibodies Muramidase Mus Nature Nitrates Paper Pathology Pathway interactions Peptide/MHC Complex Peptides Phagocytes Phase Positioning Attribute Post-Translational Protein Processing Procedures Process Progress Reports Proteins Publications Reagent Reporting Research Research Infrastructure Resources Role Specificity Structure System T-Cell Receptor T-Lymphocyte Time Tissues Transgenes Transgenic Mice Tryptophan Tyrosine United States National Institutes of Health Vesicle base cytokine density experience flexibility globular protein instrument instrumentation interest member professor receptor research study response synthetic peptide

项目摘要

DESCRIPTION (provided by applicant): The purpose of our research is to explain antigen presentation by class II MHC molecules having a strong biochemical, quantitative and mechanistic foundation in order to avoid the many empiricisms that dominate this complex area. We investigated how the model protein antigen hen egg-white lysozyme (HEL) was processed by antigen presenting cells (APC); and established the chemical basis for the processing, selection by, and binding of, its various peptides to I-Ak molecules. This now places us in a situation where these parameters can be strictly related to the biology of the T cell response, i.e. to the specificities and frequencies of HEL clones. The first aim of this renewal is to examine post translational modification of the HEL peptides induced when APC are activated by cytokines. Evidence is presented that activated APC can modify HEL to generate specific T cells to the modified peptides. The initial focus of examination is on HEL peptides in which their tyrosines and tryptophans are nitrated (or oxidized). The plans are to characterize the specificities of the T cells, the biology of the APC that induces the changes, and the biochemical nature of the changes using mass spectrometry approaches. The biology of the T cells to modified peptides will be examined in mice bearing a T cell receptor as a transgene; we intend to identify the possible role of the T cells in inflammation and tissue pathology focusing on beta cells expressing HEL. In the second aim, an explanation is sought for why the response to the various HEL epitopes does not relate to the number of peptide-MHC complex presented by APC. We can quantitate the density of the various peptide-MHC complexes from HEL: those represented at a high level induce about the same number of T cells as those presented at about one- or two-hundred fold less. We consider a possible number of explanations such as molecular competition, competition or cooperativity of the complexes on APC surface, the time of persistence of the complexes, and finally the modulating presence of the murine lysozyme, a strong cross-reactive protein expressed normally on APC. By knowing these important variables, we should be able to have a much fuller understanding of the CD4 T cell responses. The experiments are based on; i) using HEL molecules with relevant biochemical changes that alter either epitope expressions or the persistence of an epitope in APC, ii) tracing the cellular response with TCR receptor transgenic mice to more than one epitope, iii) using APC in transfer systems; and, iv) genetically ablating the murine lysozyme gene.

描述（由申请人提供）：我们研究的目的是解释具有强大生化、定量和机制基础的 II 类 MHC 分子的抗原呈递，以避免主导这一复杂领域的许多经验主义。我们研究了抗原呈递细胞（APC）如何加工模型蛋白抗原母鸡蛋白溶菌酶（HEL）；并建立了其各种肽与 I-Ak 分子的加工、选择和结合的化学基础。现在，我们处于这样一种情况：这些参数可以与 T 细胞反应的生物学（即 HEL 克隆的特异性和频率）严格相关。此次更新的首要目的是检查当 APC 被细胞因子激活时诱导的 HEL 肽的翻译后修饰。有证据表明，活化的 APC 可以修饰 HEL，从而产生针对修饰肽的特异性 T 细胞。检查的最初重点是 HEL 肽，其中酪氨酸和色氨酸被硝化（或氧化）。该计划旨在利用质谱方法来表征 T 细胞的特异性、诱导变化的 APC 生物学特性以及变化的生化性质。将在携带 T 细胞受体作为转基因的小鼠中检查 T 细胞对修饰肽的生物学作用；我们打算确定 T 细胞在炎症和组织病理学中的可能作用，重点关注表达 HEL 的 β 细胞。第二个目标是寻求解释为什么对各种 HEL 表位的反应与 APC 呈递的肽-MHC 复合物的数量无关。我们可以定量 HEL 中各种肽-MHC 复合物的密度：高水平的肽-MHC 复合物诱导的 T 细胞数量与低水平的肽-MHC 复合物的数量大致相同。我们考虑了多种可能的解释，例如 APC 表面复合物的分子竞争、竞争或协同性、复合物的持续时间，以及最后的鼠溶菌酶（一种在 APC 上正常表达的强交叉反应蛋白）的调节存在。通过了解这些重要变量，我们应该能够更全面地了解 CD4 T 细胞反应。实验基于； i) 使用具有相关生化变化的 HEL 分子来改变表位表达或 APC 中表位的持久性，ii) 追踪 TCR 受体转基因小鼠对多个表位的细胞反应，iii) 在转移系统中使用 APC； iv) 从基因上消除鼠溶菌酶基因。