Antigen recognition and activation of B-cell receptors of HIV-1 broadly neutralizing antibodies

HIV-1 广泛中和抗体的 B 细胞受体的抗原识别和激活

• 批准号: 10571695
• 负责人: S. Munir ALAM
• 金额: $ 88.52万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-20 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10571695
• 关键词: Acceleration; Adoptive Transfer; Affinity; Animal Model; Antigen Receptors; Antigens; Architecture; B-Cell Activation; B-Cell Antigen Receptor; B-Lymphocyte Subsets; B-Lymphocytes; Binding; Binding Sites; Biological Assay; Biophysics; Cell Line; Cell membrane; Cell surface; Chimera organism; Development; Dissociation; Event; Frequencies; Gene Deletion; Goals; HIV; HIV Receptors; HIV-1; HIV-1 vaccine; Human; Immune response; Immunoglobulin Class Switching; Immunoglobulin D; Immunoglobulin G; Immunoglobulin Genes; Immunoglobulin M; Immunoglobulin Somatic Hypermutation; In Vitro; Island; Kinetics; Knock-in; Knock-in Mouse; Ligation; Mature B-Lymphocyte; Measurement; Mediating; Membrane; Memory B-Lymphocyte; Methods; Modeling; Molecular Conformation; Mus; Phosphotransferases; Process; Property; Protein Engineering; Proteins; Receptor Activation; Resolution; Rest; Role; Signal Transduction; Signaling Molecule; Specific qualifier value; Specificity; Structure of germinal center of lymph node; Testing; Time; Vaccination; Vaccines; Viral Antigens; anergy; antigen binding; antigen test; biophysical analysis; biophysical properties; design; env Gene Products; in vivo; mutant; nanoscale; neutralizing antibody; prototype; receptor internalization; response; spatiotemporal; vaccine development

Project Summary/Abstract Elucidating the early events on the B cell surface following antigen engagement of the B cell antigen receptor (BCR) can provide an assessment of the in vivo potential of an antigen (Ag) to drive B cell activation. In contrast to the “clustering model”, the “Dissociation Activation Model” (DAM) proposes an alternate conformational state of the resting BCR and how early events on the B cell membrane initiates B cell activation. In the DAM, B cell activation is dependent on the ability of an Ag to dissociate the inactive, resting BCR oligomers (BCR conformational opening), and promote nanoscale reorganization of BCR with co-stimulatory molecules, leading to full activation. Recent advances in HIV-1 Envelope (Env) protein designs have provided several key potential immunogens, however, how such viral Ags are sensed by BCRs on B cells that participates in anti-HIV-1 immune responses that generate broadly neutralizing antibodies (bnAbs) is not well understood. The overall objective of this proposal is to bridge the quantitative biophysical and membrane dynamics measurements of Ag-BCR interactions to ex-vivo and in-vivo B cell activation in the context of the DAM. Towards this goal, we will for the first time, study and define at nanoscale resolution, Ag-induced early BCR activation events and the costimulatory signaling required for full activation of B cells expressing BCRs specifying prototype HIV bnAbs or their precursors. We hypothesize that for optimal priming HIV Env immunogens, i.e. those capable of best activating B-cells and initiating robust affinity maturation, the exposure of the BCR to the Env antigens results first in nanoscale BCR conformational opening, followed by reorganization of BCRs and co-stimulatory molecules/kinases for signal amplification on the B cell membrane. In Aim 1, we will perform biophysical analyses and study B cell membrane dynamics to define the properties of HIV Env Ag-BCR interactions for optimal activation of B cells expressing bnAb or germline precursor BCRs. In Aim 2, we will use high resolution assays to determine Ag-binding properties that induce nanoscale BCR conformational opening, the role of costimulatory and regulatory molecules and the spatio-temporal reorganization of the B cell membrane following activation with HIV Env Ags. In Aim 3, we will test evaluated Env Ags for their ability to activate and drive affinity maturation in “more amenable to induce”, (non-anergic or more “mildly” anergic) bnAb B cells in naïve knock-in (KI) repertoires. Results of such studies would be the first to allow a systematic method for predicting the potential of HIV immunogens to prime distinct bnAb precursors based on these defined Ag-induced early B cell activation events. In the long-term our studies will facilitate design and pre-selection of immunogens for testing in animal models and accelerate HIV-1 vaccine development.

项目概要/摘要 阐明 B 细胞抗原受体抗原结合后 B 细胞表面的早期事件 (BCR) 可以评估抗原 (Ag) 驱动 B 细胞激活的体内潜力。相比之下 相对于“聚类模型”，“解离激活模型”（DAM）提出了另一种构象状态 静息 BCR 的变化以及 B 细胞膜上的早期事件如何启动 B 细胞激活。在 DAM 中，B 细胞 激活取决于 Ag 解离无活性、静止的 BCR 寡聚体 (BCR 构象开放），并通过共刺激分子促进 BCR 的纳米级重组，领先 至完全激活。 HIV-1 包膜 (Env) 蛋白设计的最新进展提供了几个关键的潜力 然而，参与抗 HIV-1 的 B 细胞上的 BCR 是如何感知此类病毒 Ag 的？ 产生广泛中和抗体（bnAb）的免疫反应尚不清楚。整体 该提案的目的是架起定量生物物理和膜动力学测量的桥梁 在 DAM 的背景下，Ag-BCR 与离体和体内 B 细胞激活的相互作用。为了这个目标，我们将 首次在纳米级分辨率下研究和定义 Ag 诱导的早期 BCR 激活事件和 表达 BCR 的 B 细胞完全激活所需的共刺激信号，指定原型 HIV bnAb 或 他们的前身。我们假设，为了最佳启动 HIV 包膜免疫原，即那些能够最好地启动的免疫原。 激活 B 细胞并启动强大的亲和力成熟，导致 BCR 暴露于 Env 抗原 首先是纳米级 BCR 构象开放，然后是 BCR 重组和共刺激 用于 B 细胞膜上信号放大的分子/激酶。在目标 1 中，我们将进行生物物理学 分析和研究 B 细胞膜动力学，以确定 HIV Env Ag-BCR 相互作用的特性 表达 bnAb 或种系前体 BCR 的 B 细胞的最佳激活。在目标 2 中，我们将使用高分辨率 测定诱导纳米级 BCR 构象开放的 Ag 结合特性的测定， 共刺激和调节分子以及 B 细胞膜的时空重组 用 HIV Env Ags 激活。在目标 3 中，我们将测试评估的环境 Ag 的激活和驱动能力 “更容易诱导”（非无能或更“轻度”无能）bnAb B 细胞中的亲和力成熟 敲入（KI）曲目。此类研究的结果将是第一个允许采用系统方法来预测的结果 HIV 免疫原基于这些定义的 Ag 诱导的早期 B 来引发不同的 bnAb 前体的潜力 细胞激活事件。从长远来看，我们的研究将有助于免疫原的设计和预选 动物模型测试并加速 HIV-1 疫苗的开发。

项目成果

Plasma membrane topography governs the 3D dynamic localization of IgM B cell antigen receptor clusters.

• DOI: 10.15252/embj.2022112030
• 发表时间: 2023-02-15
• 期刊: The EMBO journal

B cells expressing IgM B cell receptors of HIV-1 neutralizing antibodies discriminate antigen affinities by sensing binding association rates.

• DOI: 10.1016/j.celrep.2022.111021
• 发表时间: 2022-06-28
• 期刊: CELL REPORTS
• 影响因子: 8.8
• 作者: Hossain, Md. Alamgir;Anasti, Kara;Watts, Brian;Cronin, Kenneth;Derking, Ronald;Groschel, Bettina;Kane, Advaiti Pai;Edwards, R. J.;Easterhoff, David;Zhang, Jinsong;Rountree, Wes;Ortiz, Yaneth;Saunders, Kevin;Schief, William R.;Sanders, Rogier W.;Verkoczy, Laurent;Reth, Michael;Alam, S. Munir
• 通讯作者: Alam, S. Munir