Induction of neutralizing antibodies targeting CD4 binding region of HIV-1 Env

诱导针对 HIV-1 Env 的 CD4 结合区的中和抗体

• 批准号: 7645923
• 负责人: Shan Lu
• 金额: $ 185.76万
• 依托单位: UNIV OF MASSACHUSETTS MED SCH WORCESTER
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-08-07 至 2014-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7645923
• 关键词: Induction; neutralizing; antibodies; targeting; CD4

DESCRIPTION (provided by applicant): The overall objective of this multi-project HIVRAD program application is to elicit neutralizing antibodies that target the CD4 binding site (CD4bs) of primary HIV-1 envelope (Env) glycoproteins. This P01 program proposal consists of three major projects, plus two cores to support the activities of major projects. The following is a summary of major activities as proposed in different Projects/Cores of this program. Goal 1: To organize and manage a highly interactive and productive research team (Core B). Goal 2: To understand how the variation in HIV-1 R5 Envs affect tropism, neutralization and vaccine development (Project 1). HIV-1 R5 envelopes vary extensively in their capacity to infect macrophages. We propose to investigate the impact of variation in macrophage tropism (mac-tropism) on other biological properties associated with Env including neutralization sensitivity. Goal 3: To study how the variation of antigenicity of CD4bs will affect the neutralization sensitivity and immunogenicity of primary Env proteins (Project 2). The CD4bs antigenicity of several panels of primary Envs, each with their own unique biological features, will be probed by mAbs. We will examine whether high CD4bs antigenicity and high sensitivity to CD4bs mAb mediated neutralization will lead to high immunogenicity for key representative Env using the DMA prime-protein boost immunization approach. Goal 4: To study the modification of receptor binding site as an approach to HIV-1 vaccine design (Project 3). We will test whether changes resulting from specific glycan modifications will lead to increased stability or accessibility of conserved epitopes in the receptor binding site and whether greater accessibility of these conserved sites will enhance their function as immunogen to elicit cross-reactive NAb responses. Goal 5: To provide support to major projects on structure analysis of Env and to study the structure of novel antigens, and antigen-antibody interactions (Core A). PROJECT 1: Variation in HIV-1 R5 Envs: Consequences for tropism, neutralization and vaccines (Chapham, P) PROJECT 1 DESCRIPTION (provided by applicant): HIV-1 R5 viruses vary considerably in phenotypes, including macrophage-tropism and sensitivity to neutralizing antibodies. Thus, highly mac-tropic envelopes (envs) exploit low amounts of CD4 and/or CCR5 for infection and contrast with non-mac-tropic R5 envs that require high CD4 levels and infect macrophages inefficiently. The capacity of highly mac-tropic envs to use low CD4/CCR5 suggests that such variants may confer a broader tropism among other CD4+ cell types that express low receptor levels and may have an advantage during virus transmission. Our recent data, using neutralizing monoclonal antibodies (mAbs) and entry inhibitors, strongly suggests that highly mac-tropic R5 envs carry a more exposed CD4 binding site (CD4bs) and may be vulnerable to neutralizing antibodies (NAbs) induced by vaccines. We propose to extensively investigate tropism and neutralization sensitivity of diverse R5 envs in the following four aims: Aim 1. The effect of HIV-1 R5 macrophage-tropism on infection of different CD4+ cell populations. We will examine whether highly mac-tropic R5 envelopes confer a broader tropism among CD4+ T-cell populations. Aim 2. Further analysis of the envelope determinants for macrophage infection and use of low CD4 in clade B and non-clade B envelopes. We will analyze clade B and non-clade B envs to identify determinants of tropism and to further examine the role of the CD4 binding loop. Aim 3. Investigation of the impact of R5 env variation in macrophage-tropism on sensitivity to neutralizing antibodies. We will investigate how R5 env variation impacts on sensitivity to HIV-1 + human sera, neutralizing mabs and vaccine induced neutralizing antibodies. Aim 4. Development and characterization of bacterially-produced, unglycosylated protein constructs that mimic the CD4bs. We have designed and produced CD4bs mimics that carry the critical elements of the CD4bs in an unglycosylated peptide that can be produced in bacteria. These CD4bs mimics bind CD4 and b12. Their structure and capacity to induce neutralizing antibodies will be investigated. We expect to provide important insights into (1) the variation of R5 envs for tropism and neutralization sensitivity, (2) the env amino acids and structural determinants involved in varying tropism and neutralization sensitivity and (3) the impact of this variation in the design of novel env-based vaccines.

描述（由申请人提供）：该多项目Hivrad程序应用的总体目标是引起靶向主要HIV-1 Invelope（ENG）糖蛋白的CD4结合位点（CD4B）的中和抗体。该P01计划提案包括三个主要项目，以及两个核心，以支持主要项目的活动。以下是该计划的不同项目/核心中提出的重大活动的摘要。目标1：组织和管理一个高度互动和富有成效的研究团队（Core B）。目标2：了解HIV-1 R5 ENV中的变化如何影响鹿，中和和疫苗的发展（项目1）。 HIV-1 R5包膜在感染巨噬细胞的能力方面差异很大。我们建议研究巨噬细胞对巨噬细胞主义（MAC-Tropism）对与ENV相关的其他生物学特性（包括中和敏感性）的影响。目标3：研究CD4BS抗原性的变化如何影响原代ENV蛋白的中和敏感性和免疫原性（项目2）。 MAB将探测几个主要Envs的CD4BS抗原性，每个Envs具有其独特的生物学特征。我们将检查使用DMA Prime蛋白增强免疫方法的关键代表性ENV的高CD4BS抗原性和对CD4BS mAb介导的中和的高灵敏度是否会导致高免疫原性。目标4：研究受体结合位点作为HIV-1疫苗设计方法的修饰（项目3）。我们将测试特定的聚糖修饰引起的变化是否会导致受体结合位点中保守表位的稳定性或可及性的提高，以及这些保守位点的更大可及性是否会增强其作为免疫原的功能，以引起交叉反应性NAB反应。目标5：为ENV结构分析的主要项目提供支持，并研究新型抗原和抗原抗体相互作用的结构（核心A）。 项目1：HIV-1 R5 Envs中的变化：对潮流，中和和疫苗的后果 （Chapham，P） 项目1描述（由申请人提供）：HIV-1 R5病毒在表型中有很大不同，包括巨噬细胞 - 热态和对中和抗体的敏感性。因此，高度MAC-热带信封（ENVS）利用低量的CD4和/或CCR5感染，并与需要高CD4水平并降低巨噬细胞的非MAC-热带R5 ENC对比。高度Mac-Tropic Env使用低CD4/CCR5的能力表明，此类变体可能会在其他表达低受体水平的CD4+细胞类型中赋予更广泛的热带主义，并且在病毒传播过程中可能具有优势。我们最近使用中和单克隆抗体（MAB）和进入抑制剂的数据强烈表明，高度MAC-Tropic R5 Envs具有更暴露的CD4结合位点（CD4BS），并且可能容易受到疫苗诱导的抗体（NABS）的影响。我们建议在以下四个目的中广泛研究不同R5 ENV的端主和中和敏感性：AIM 1。HIV-1 R5巨噬细胞 - 热 - 热 - 热噬菌体对不同CD4+细胞种群感染的影响。我们将检查高度Mac-Tropic R5信封是否赋予CD4+ T细胞种群中更广泛的热带主义。目标2。对巨噬细胞感染的包膜决定因素的进一步分析，以及在进化枝B和非层B信封中使用低CD4。我们将分析进化枝B和非脱落B ENV，以识别托拉邦的决定因素，并进一步检查CD4结合环的作用。 AIM 3。研究R5 Env变异对巨噬细胞 - 热 - 对中和抗体敏感性的影响。我们将研究R5 Env的变异如何影响对HIV-1 +人血清的敏感性，中和MAB和疫苗诱导的中和抗体。 AIM 4。模仿CD4B的细菌生产的，未糖基化的蛋白质构建体的发展和表征。我们设计和生产了CD4B的模拟物，这些CD4BS在可在细菌中产生的非糖基化肽中带有CD4B的关键元素。这些CD4B模仿CD4和B12。它们的结构和诱导中和抗体的能力将进行研究。我们期望对（1）R5 Envs对向流和中和敏感性的变化提供重要的见解，（2）ENV氨基酸和参与变化的热态和中和敏感性的结构决定因素以及（3）这种新型ENV疫苗设计中这种变化的影响。