Coincident Antigen Processing Pathways Feed M1 and M2 MHC Class II Conformers

一致抗原加工途径喂养 M1 和 M2 MHC II 类适形者

• 批准号: 10303345
• 负责人: James R Drake
• 金额: $ 24.45万
• 依托单位: ALBANY MEDICAL COLLEGE
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-06-07 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10303345
• 关键词: Antigen Presentation; Antigen Targeting; Antigen-Presenting Cells; Antigens; Attenuated; Autoimmunity; B-Cell Activation; B-Cell Antigen Receptor; B-Lymphocytes; Biochemical; Biological; CD4 Positive T Lymphocytes; Charge; Complex; Data; Dimerization; Dissociation; Dose; Endosomes; Exhibits; Fluorescence Resonance Energy Transfer; Foundations; Goals; Haptens; Histocompatibility Antigens Class II; Immune response; Immune system; Immunologics; Interphase Cell; Kinetics; Label; Laboratories; Lead; Liquid substance; MHC Class II Genes; Mainstreaming; Mass Spectrum Analysis; Mediating; Modeling; Molecular; Molecular Conformation; Molecular Genetics; Monoclonal Antibodies; Pathway interactions; Peptide Hydrolases; Peptide/MHC Complex; Peptides; Phase; Physiologic pulse; Process; Property; Proteomics; Publishing; Receptor Signaling; Reporting; Research Proposals; Rest; Role; Signal Transduction; Site; Source; Structure; T cell response; T-Cell Activation; Testing; Therapeutic; Transmembrane Domain; Vaccines; Work; antigen binding; antigen processing; base; comparative; conformer; genetic approach; immune activation; in vivo; insight; novel; novel strategies; novel therapeutic intervention; pathogen; peptide B; receptor binding; response; therapeutic target; Antigen Presentation; Antigen Targeting; Antigen-Presenting Cells; Antigens; Attenuated; Autoimmunity; B-Cell Activation; B-Cell Antigen Receptor; B-Lymphocytes; Biochemical; Biological; CD4 Positive T Lymphocytes; Charge; Complex; Data; Dimerization; Dissociation; Dose; Endosomes; Exhibits; Fluorescence Resonance Energy Transfer; Foundations; Goals; Haptens; Histocompatibility Antigens Class II; Immune response; Immune system; Immunologics; Interphase Cell; Kinetics; Label; Laboratories; Lead; Liquid substance; MHC Class II Genes; Mainstreaming; Mass Spectrum Analysis; Mediating; Modeling; Molecular; Molecular Conformation; Molecular Genetics; Monoclonal Antibodies; Pathway interactions; Peptide Hydrolases; Peptide/MHC Complex; Peptides; Phase; Physiologic pulse; Process; Property; Proteomics; Publishing; Receptor Signaling; Reporting; Research Proposals; Rest; Role; Signal Transduction; Site; Source; Structure; T cell response; T-Cell Activation; Testing; Therapeutic; Transmembrane Domain; Vaccines; Work; antigen binding; antigen processing; base; comparative; conformer; genetic approach; immune activation; in vivo; insight; novel; novel strategies; novel therapeutic intervention; pathogen; peptide B; receptor binding; response; therapeutic target

Summary: The current mainstream view of exogenous antigen processing postulates a pool of proteases processing exogenous antigen within the endosome, with structurally homogeneous MHC class II (MHCII) molecules randomly capturing resultant peptides. However, this view is an oversimplification on at least two levels. First, work from multiple laboratories including our own has shown that MHCII molecules exist in two distinct conformational states based on alternative pairing of transmembrane domain GxxxG dimerization motifs (i.e., M1 and M2 paired MHCII) and that these two MHCII conformers have distinct biological and immunological properties. Second, we have reported that in B lymphocytes M1 and M2 paired MHCII molecules are selectively loaded with peptide derived from different pools of exogenous antigen. M1 MHCII is loaded with peptide derived from B cell receptor (BCR)-bound cognate antigen, whereas peptide derived from non-cognate antigen is loaded onto both M1 and M2 MHCII. New preliminary data also reveals that ~50% of the peptides bound to each conformer are unique to that set of molecules. As engagement of M1 and M2 peptide-MHCII drive different levels of B and T cell activation, differential MHCII conformer peptide loading will impact the focus, strength and quality of an immune response. This framework leads to the hypothesis that within an antigen presenting cells, there are two coincident but distinct pathways of exogenous antigen processing that leads to selective peptide loading onto M1 versus M2 paired MHCII molecules. The goal of this proposal is to define the two pathways of exogenous antigen processing that feed the two MHCII conformers. This goal will be attained by completing two Specific Aims. The objective of the first aim is to define/analyze the peptidomes of M1 and M2 paired MHCII isolated from both resting and antigen-pulsed B cells. This information will point to the subcellular sites of processing for M1 vs. M2 MHCII-bound peptides by defining the pool of source antigens for each MHCII conformer. The results will also reveal the impact of antigen targeting as well as BCR signaling-induced changes in the antigen processing pathway on the M1 and M2 MHCII peptidomes. The objectives of the second aim are to; 1) take a molecular genetics approach to define the structure and dynamics of the MHCII peptide loading complex (PLC) that selectively charges peptides from BCR-bound cognate antigen onto M1 MHCII and 2) to use a discovery- style approach to identify and characterize new PLC components. The potential impact of these studies is many-fold. For example, results will reveal how the form of antigen (e.g., vaccine) provided to the immune system would impact the levels of M1 and M2 MHCII peptide loading and thus the level of subsequent immune activation. Therapeutically, the ability to selectively interfere with M1 or M2 MHCII-restricted antigen presentation may lead to new therapeutic approaches to selectively control/block autoimmunity, while leaving the immune response to pathogens comparatively unimpaired.

概括： 当前的外源抗原加工的主流视图假设蛋白酶加工池 内源性抗原内体内，具有结构均匀的MHC II类（MHCII）分子 随机捕获产生的肽。但是，这种观点至少在两个级别上过度简化。第一的， 来自包括我们自己在内的多个实验室的工作表明，MHCII分子存在于两个不同的不同 基于跨膜结构域GXXXG二聚体基序的替代配对的构象状态（即 M1和M2配对MHCII），并且这两个MHCII构象异构体具有独特的生物学和免疫学 特性。其次，我们报告说，在B淋巴细胞和M2配对的MHCII分子中是 选择性地用源自不同的外源抗原池的肽。 M1 MHCII已加载 源自B细胞受体（BCR）结合同源抗原的肽 将抗原加载到M1和M2 MHCII上。新的初步数据还表明，约有50％的肽 与每个构象异构体结合是该分子唯一的。作为M1和M2肽MHCII的参与度 驱动不同水平的B和T细胞激活，差异MHCII构象构肽载荷将影响 免疫反应的重点，力量和质量。 该框架导致以下假设：在抗原呈现细胞中，有两个重合 但是，外源抗原加工的不同途径，导致选择性肽在M1上的选择性 M2配对的MHCII分子。该建议的目的是定义外源抗原的两种途径 处理两个MHCII构象体的处理。通过完成两个具体目标来实现此目标。 第一个目的的目的是定义/分析从从中分离出的M1和M2配对的肽组 静止和抗原脉冲的B细胞。该信息将指向M1处理的亚细胞位点 通过定义每个MHCII构象异构体的源抗原池与M2 M2结合的肽。结果 还将揭示抗原靶向以及BCR信号诱导的抗原变化的影响 M1和M2 MHCII肽组上的处理途径。第二个目标的目标是1） 分子遗传学方法来定义MHCII肽加载复合物（PLC）的结构和动力学 这有选择地将来自BCR结合的同源抗原的肽收取M1 MHCII和2）使用发现 - 识别和表征新PLC组件的样式方法。 这些研究的潜在影响是多种的。例如，结果将揭示抗原的形式如何 （例如，提供给免疫系统的疫苗）会影响M1和M2 MHCII肽负荷的水平 因此，随后的免疫激活水平。在治疗上，有选择性干扰M1的能力 或M2 MHCII限制的抗原表现可能会导致新的治疗方法 控制/阻止自身免疫，同时使病原体的免疫反应相对未受损。