Pure and Authentic HIV-1 Env Immunogens

纯正的 HIV-1 包膜免疫原

• 批准号: 8141068
• 负责人: JAMES M BINLEY
• 金额: $ 45.5万
• 依托单位: TORREY PINES INST FOR MOLECULAR STUDIES
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2014-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8141068
• 关键词: Animals; Antigens; Area; Binding; Collaborations; Development; Epitopes; Exhibits; Flow Cytometry; Fluorochrome; Goals; HIV-1; Immune Sera; Immunity; Immunization; Immunoglobulin G; Infection; Kinetics; Label; Left; Memory B-Lymphocyte; Methods; Oryctolagus cuniculus; Particulate; Patients; Resistance; Serum; Specificity; Surface; Testing; Ursidae Family; Vaccine Design; Vaccine Research; Vaccines; Virion; Virus-like particle; Work; base; env Glycoproteins; immunogenic; immunogenicity; indexing; neutralizing antibody; neutralizing monoclonal antibodies; particle; prospective; response; theories; tool; vaccine candidate

DESCRIPTION (provided by applicant): Broadly neutralizing antibodies (bnAbs) are expected to be a crucial component of vaccine-elicited protective immunity against HIV-1. However, all attempts to elicit such responses to date have failed. The lack of progress in this area could relate to the insufficient authenticity of candidate immunogens. A consistent finding of immunogenicity studies has been that while immune sera efficiently bind to the index immunogen, few Abs recognize the native form of Envelope glycoprotein (Env) found on virus particles. Because nAbs have the select ability to bind to these Env trimers, we hypothesize that Env trimers may in turn be the only antigen capable of selectively and reliably inducing nAbs in a vaccine setting. Testing this hypothesis has until now been impossible, due to problems in isolating pure native Env trimers. For example, particulate vaccines bear many non-functional forms of Env on their surfaces, as well as native trimers. These alternative forms of Env are "promiscuous", in that they are recognized by non-neutralizing Abs (non-nAbs). As a result, they interfere with the development of nAbs. Here we describe new methods to completely eliminate non-functional Env, which will allow us to isolate and test pure authentic Env trimers as vaccines. Our Specific Aims are: Specific Aim 1: To produce virus-like particles bearing authentic Env trimers as the sole form of Env. We are attempting to eliminate non-functional Env from particles, leaving only intact trimers. New strategies have brought us close to achieving this goal. Specific Aim 2: To generate soluble forms of pure authentic Env trimers. We are investigating methods to purify authentic soluble Env trimers. The antigenic topology and stability of pure soluble trimers will be characterized. Specific Aim 3: To evaluate pure authentic trimer immunogens in rabbits. The results from immunizations of successive groups of animals will guide improvements in the consistency, magnitude and breadth of nAb responses. The kinetics, duration and specificity of nAb responses will be characterized. Specific Aim 4: To rescue broadly neutralizing monoclonal antibodies using pure trimer VLPs as "bait". BnmAbs are useful tools for vaccine design. Pure authentic Env trimers may be ideal "baits" for selecting memory B cells, allowing new bnmAbs to be rescued. We will generate fluorochrome-labeled baits and work in collaboration with a group who has recently demonstrated a flow cytometry method to rescue new bnmAbs from HIV-1-infected donors. The neutralization potency, breadth and specificity of any newly identified bnmAbs will be determined. We will also examine IgG sequences and the extent of divergence from the germline. PUBLIC HEALTH RELEVANCE: We hypothesize that pure native HIV-1 Env trimers can elicit effective nAb responses. We will use a new strategy to produce VLPs bearing only authentic Env trimers. By similar methods, we will generate fully authentic soluble Env trimers. Their ability to elicit nAbs will be compared to mock immunogens.

描述(由申请人提供)：广谱中和抗体(BNAbs)有望成为疫苗诱导的针对HIV-1的保护性免疫的重要组成部分。然而，到目前为止，所有争取此类回应的尝试都以失败告终。这一领域缺乏进展可能与候选免疫原真实性不足有关。免疫原性研究的一致发现是，虽然免疫血清有效地与指数免疫原结合，但很少有抗体识别病毒颗粒上发现的天然形式的包膜糖蛋白(Env)。由于NAB具有与这些Env三聚体结合的选择能力，我们假设Env三聚体可能反过来是在疫苗环境中能够选择性和可靠地诱导NAB的唯一抗原。到目前为止，由于分离纯本地环境三聚体存在问题，验证这一假说是不可能的。例如，颗粒疫苗在其表面带有许多非功能性形式的环境病毒，以及天然的三聚体。这些替代形式的环境病毒是“混杂的”，因为它们被非中和抗体(非NAB)识别。因此，它们干扰了国家适应行动计划的发展。在这里，我们描述了完全消除非功能Env的新方法，这将使我们能够分离和测试纯正的Env三聚体作为疫苗。我们的具体目标是： 具体目标1：生产含有真实环境三聚体的病毒样颗粒，作为环境病毒的唯一形式。我们正试图从粒子中消除不起作用的Env，只留下完整的三聚体。新的战略使我们接近实现这一目标。 具体目标2：产生纯正的环境三聚体的可溶性形式。我们正在研究提纯真正的可溶性环境三聚体的方法。将对纯可溶性三聚体的抗原性、拓扑结构和稳定性进行表征。 具体目的3：评价纯正的三聚体免疫原在兔体内的免疫效果。连续几组动物的免疫结果将指导NAB反应的一致性、大小和广度的改进。将描述NAB反应的动力学、持续时间和特异性。 具体目的4：以纯三聚体VLP为“诱饵”抢救广谱中和单抗。BnmAbs是疫苗设计的有用工具。纯正的Env三聚体可能是选择记忆B细胞的理想“诱饵”，从而挽救新的bnmAbs。我们将产生荧光标记的诱饵，并与最近展示了一种流式细胞术方法的一个小组合作，从感染HIV-1的捐赠者那里拯救新的bnmAb。将确定任何新鉴定的bnmAbs的中和效力、广度和特异性。我们还将检查免疫球蛋白序列和与生殖系的差异程度。 公共卫生相关性：我们假设纯天然HIV-1环境三聚体可以引起有效的NAB反应。我们将使用一种新的策略来生产仅带有正宗环境三聚体的VLP。通过类似的方法，我们将产生完全真实的可溶性环境三聚体。他们诱导nabs的能力将被与模拟免疫原进行比较。