Fusion peptide directed immunogens that elicit neutralizing and protective antibodies in non-human primates

融合肽定向免疫原可在非人灵长类动物中引发中和和保护性抗体

• 批准号: 10337312
• 负责人: Shane P Crotty
• 金额: $ 90.67万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-03-18 至 2025-02-28
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10337312
• 关键词: 2019-nCoV; 3-Dimensional; Address; Affinity; American; Animals; Antibodies; Antibody Response; Antigens; Attenuated; Autologous; Avidity; B-Cell Antigen Receptor; B-Lymphocytes; Bolus Infusion; COVID-19; COVID-19 vaccine; Cells; Complex; Consensus Sequence; Data; Development; Dose; Electron Microscopy; Engineering; Epitopes; Future; Glycoproteins; Goals; Grant; HIV; HIV vaccine; HIV-1; Human; Image; Immune response; Immune system; Immunization; Immunize; Immunoglobulin G; Immunoglobulin Somatic Hypermutation; Immunologics; Individual; Left; Longitudinal Studies; Maps; Mediating; Membrane Glycoproteins; Modeling; Monkeys; Needles; Pathogenicity; Patients; Peptide Vaccines; Peptide antibodies; Peptides; Pilot Projects; Polysaccharides; Public Health; Reaction; Regimen; Reproducibility; Research; Sampling; Secondary Immunization; Series; Serum; Site; Structure; Structure of germinal center of lymph node; Surface; Techniques; Testing; Vaccine Research; Vaccines; Viral; Virus; Wild Type Mouse; Work; base; cell envelope; deltoid muscle; design; efficacy testing; experimental study; immunogenic; improved; interest; nanoparticle; neutralizing antibody; nonhuman primate; novel; pandemic disease; polyclonal antibody; programs; protective efficacy; reconstruction; response; simian human immunodeficiency virus; success; trafficking; vaccination strategy; vaccine candidate; vaccine development; vaccine strategy; vaccine trial

Abstract/Project Summary HIV-1 envelope glycoprotein (Env) is the sole target for development of antibody-mediated immune response. Studies of patients infected with HIV have led to the isolation of antibodies against different epitopes on the Env surface, capable of neutralizing a broad range of circulating HIV strains and providing passive protection against repeated viral challenges in non-human primates (NHPs). The current goal of HIV vaccine research is to create immunogens capable of eliciting similar antibody responses in naïve individuals. Structure- based engineering of the soluble ectodomain of Env trimer is in the core of most of the current approaches. One major complicating factor with this approach comes from the large antigenic surface on the Env, where many off-target and competing epitopes are available to the immune system. The induction of immune responses against “distracting” epitopes leads to attenuated and inconsistent response against the targeted bnAb epitopes of interest. NHPs are an important model for this work, because wildtype mice do not make Ab responses to major Env nAb epitopes observed in humans. Analysis of the polyclonal Ab response in NHP immunizations where soluble Env ectodomain trimers were used, revealed a set of highly immunogenic epitopes with low potential for the development of protective heterologous, and in some cases even autologous, responses. These epitopes include the base of the Env trimer ectodomain, N241/N289 glycan hole and variable loops (V1-V5). To address this shortcoming we have developed a rational approach to consistently elicit antibodies against the conserved fusion peptide (FP) epitope, for which there are several examples of human bnAbs. We have used our designer trimers and continuous antigen release program to generate preliminary results verifying success of this concept in NHPs. The reproducibility of the epitope targeting is the most impressive preliminary result presented here, and it indicates that reproducible elicitation of FP nAbs in humans may be readily achievable. Here we propose to conduct a series of experiments designed to further optimize this immunization strategy by minimizing the accessibility of immuno-distracting, off-target epitopes, and ultimately verify if protective, FP-targeting, bnAbs can be reproducibly elicited in NHPs. We intend to also immunize some animals in parallel with a SARS-CoV2 RBD immunogen we have designed. The RBD immunizations will be at a different site (deltoid) and will not interfere with the Env fusion peptide targeted immunizations. This dual use immunization approach is generally valuable for future HIV vaccine studies, and we will perform a pilot study to show this type of dual use immunization strategy is informative, which will be of value to use in our future HIV vaccine studies. The SARS-CoV2 RBD will also serve as a negative control for immunological parameters compared to the HIV candidate vaccine, which is of additional value. We will also incorporate our immunogens into multi-valent nanoparticles to improve immunogen trafficking, enhance B cell receptor avidity, and block the non-productive but highly immunogenic base epitope. Further, we will use continuous antigen delivery to improve the duration of germinal center reactions, and ultimately drive the high levels of somatic hypermutation necessary for generating bnAbs capable of neutralizing a wide diversity of HIV strains. This project will culminate by testing the efficacy of our vaccine regimen by challenging immunized NHPs with heterologous low dose repeated challenge.

摘要/项目摘要 HIV-1包膜糖蛋白（ENV）是抗体介导的免疫响应开发的唯一靶标。对感染HIV的患者的研究导致对ENV表面上不同表位的抗体分离，能够中和广泛的循环HIV菌株，并为非人类素数（NHP）中反复的病毒挑战提供了被动保护。 HIV疫苗研究的当前目标是创建能够在幼稚个体中引起类似抗体反应的免疫原子。 Env Trigger的实体外域的基于结构的工程是当前大多数方法的核心。这种方法的一个主要复杂因素来自ENV上的大型抗原表面，在该表面上，免疫系统可供选择许多脱靶和竞争表位。免疫学反应对“分心”表位的诱导反应导致对目标BNAB感兴趣的BNAB表位的衰减和不一致的反应。 NHP是这项工作的重要模型，因为野生型小鼠不会对人类观察到的主要ENV NAB表位做出AB反应。使用固体Env胞外三聚体的NHP免疫中的多克隆AB反应分析，显示了一组高度免疫原性的表位，具有较低潜力的受保护异源的潜力，在某些情况下甚至自体反应。这些表位包括ENV三聚体外生域，N241/N289 Glycan孔和可变环（V1-V5）的基部。为了解决这一缺点，我们开发了一种理性的方法，以始终如一地引起针对保守的融合肽（FP）发作的抗体，为此有几个例子。我们已经使用了设计器的三聚机和连续的抗原释放程序来生成初步结果，以验证NHP中此概念的成功。表位靶向的可重复性是此处介绍的最令人印象深刻的初步结果，这表明可以很容易地实现对人类FP NAB的可重复启发。在这里，我们建议进行一系列实验，旨在通过最大程度地降低免疫分裂，脱靶表位的可及性来进一步优化这种免疫策略，并最终验证是否可以在NHP中重现保护性，FP靶向BNAB。我们还打算与我们设计的SARS-COV2 RBD免疫原样对某些动物进行免疫。 RBD免疫抑制作用将在不同的部位（三角肌），不会干扰融合肽靶向的免疫抑制。这种双重使用免疫抑制方法通常对于未来的HIV疫苗研究很有价值，我们将进行一项试点研究，以表明这种双重使用免疫抑制策略是有益的，在我们未来的HIV疫苗研究中，这将是有价值的。与HIV候选疫苗相比，SARS-COV2 RBD还将作为免疫学参数的负面对照。我们还将将免疫原纳入多价纳米颗粒中，以改善免疫原料运输，增强B细胞受体的亲和力，并阻止非生产力但高度免疫原性的基础表位。此外，我们将使用持续的抗原递送来改善生发中心反应的持续时间，并最终驱动产生能够中和能够中和多样性HIV菌株的BNAB所需的高水平体外超突变。该项目将通过挑战以异源的低剂量重复挑战来测试疫苗方案的有效性，从而达到最终结束。