T Cell Antigen Recognition

T细胞抗原识别

• 批准号: 7928373
• 负责人: ELLIS L REINHERZ
• 金额: $ 45.09万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-22 至 2012-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7928373
• 关键词: Accounting; Affect; Affinity; Antibodies; Antigen-Presenting Cells; Antigens; Autoimmune Process; Award; Binding; Binding Sites; C-terminal; CD3 Antigens; Cell surface; Complex; Development; Electron Spin Resonance Spectroscopy; Elements; Environment; Escherichia coli; Event; Fetal Thymic Organ Culture; Funding; Grant; Histocompatibility Antigens Class II; Human; Immunologic Deficiency Syndromes; Ligands; Ligation; Liposomes; MHC Class I Genes; MHC Class II Genes; MHC Interaction; Measurement; Measures; Mediating; Membrane; Methods; Modeling; Molecular; Molecular Conformation; Monoclonal Antibodies; Mutation; Nature; Peptide/MHC Complex; Peptides; Relative (related person); Role; Shapes; Side; Signal Transduction; Solutions; Spin Labels; Structure; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; Techniques; abstracting; base; design; dimer; insight

ABSTRACT During the last funding interval as a merit award, this grant focused on the T cell receptor (TCR) complex composed of an ¿¿ heterodimer and non-covalently associated CD3 signaling components. We continued crystallographic analysis with TCRs, providing the first structure of an ¿¿ heterodimer in complex with a peptide/MHC (pMHC) class II ligand. In conjunction with a crystallographic structure of CD4 D1D2 binding to the same MHC class II molecule, a hydrophobic concavity formed by residues from membrane proximal ¿2 and ¿2 MHC class II domains was revealed. We excluded a direct TCRab-CD4 interaction, instead revealing how TCR¿¿ and CD4 signaling is coordinated in a "V-shape" around the antigenic peptide/pMHC class II complex. Solution structures of CD3¿¿ and CD3¿¿ ectodomain complexes were determined by NMR, uncovering for each dimer a unique side-to-side hydrophobic interface between their two Ig-like domains with parallel pairing of respective C-terminal ¿-strands, and suggesting how rigidified CD3 elements participate in TCR-based signal transduction. To now characterize the structural basis for early signal transduction events via this TCR¿¿ complex, four aims are proposed involving the CD3¿¿ heterodimer and associated TCR ¿ chain. First, NMR-based methods will be used to determine the precise binding site on CD3¿¿ of activating and non-activating anti-CD3¿ mAbs, given equivalent binding affinities. Second, CD3¿¿-associated TCR¿ chain recognition function during thymic development and T cell activation accounting for V¿ repertoire bias will be assessed. Third, the structure and function of the transmembrane (TM) segments of CD3¿ and ¿ will be determined and their interaction with that of TCR ¿ ascertained. Fourth, electron paramagnetic resonance (EPR) methods will be exploited to define the orientation and disposition of TM elements and how pMHC or anti-CD3¿ mAbs affect TM depth, orientation and structural conformation. Distance measurements between the ¿ chain and CD3¿ and CD3¿ ectodomains will also be examined before and after pMHC or anti- CD3 mAb ligation. That orthological rather than vertical force via CD3 components activates T cells suggests a dynamic mechanosensor TCR model; pMHC pulls on the TCR from the opposing antigen-presenting cell surface such that the ¿¿ heterodimer then presses on the CD3 ectodomains to initiate signaling.

抽象的 在上次融资间隔作为功绩奖励期间，该赠款重点介绍了T细胞接收器（TCR）综合体 由€€heterodimer和无共价相关的CD3信号成分组成。我们继续 用TCRS进行晶体学分析，提供了复杂的异二聚体的第一个结构 肽/MHC（PMHC）II类配体。与CD4 D1D2结合的结晶结构结合 相同的MHC II类分子，一种由膜近端残留物形成的疏水凹陷 »揭示了2个MHC II类领域。我们排除了直接的TCRAB-CD4相互作用，而是揭示 TCR€和CD4信号如何在抗原辣椒/PMHC II类周围的“ V形”中协调 复杂的。 CD3¿和CD3 ?? ECTODOMAIN复合物的溶液结构由NMR确定 在每个二聚体的两个Ig样域之间露出唯一的左右疏水界面 相对C末端� -Strands的平行配对，并暗示CD3元素如何参与 基于TCR的信号传输。现在表征早期信号传输事件的结构基础 通过这种tcr。提出了四个目标，涉及CD3“异二聚体和相关的TCR€ 链。首先，基于NMR的方法将用于确定激活CD3€上的精确结合位点 给定等效的结合亲和力，和非激活的抗CD3？mAb。其次，cd3 ?? - 相关 TCR¿胸膜发育过程中的链识别函数和T细胞激活核算V¿曲目 偏见将被评估。第三，CD3C和€的跨膜（TM）段的结构和功能 将确定并确定其与TCR的相互作用。第四，电子顺磁性 将探索共振（EPR）方法，以定义TM元素的方向和处置以及如何定义 PMHC或抗CD3？MAB会影响TM深度，方向和结构构象。距离测量 在PMHC或抗抗之前，还将检查链和CD3链和CD3 ectodomain之间 CD3 mAb连接。通过CD3组分激活T细胞的正交作用而非垂直力表明 动态机械传感器TCR模型； PMHC从相反的抗原呈递细胞中拉出TCR 表面使得异二聚体随后按下CD3外生域以启动信号传导。