Structural and functional evaluation ofde novo-designed, two-component nanoparticle carriers for HIV Env trimer immunogens
Structural and functional evaluation ofde novo-designed, two-component nanoparticle carriers for HIV Env trimer immunogens
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DOI：
10.1371/journal.ppat.1008665
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发表时间：
2020-08-01
期刊：
影响因子：
6.7
通讯作者：
Ward, Andrew B.
中科院分区：
文献类型：
--
作者：
Antanasijevic, Aleksandar;Ueda, George;Ward, Andrew B.
双组分自组装纳米颗粒代表了多价呈递病毒抗原的通用平台。具有不同尺寸和几何形状的蛋白质纳米颗粒的计算设计使得能够与所选择的抗原组合以测试免疫策略中的新型多聚化概念，其中目标是改善中和抗体谱系的诱导和成熟。在这里，我们描述了详细的抗原，结构和功能表征的计算设计的四面体，八面体和二十面体纳米颗粒免疫原显示三聚体HIV包膜糖蛋白（Env）胞外域。将基于亚型A（BG 505）或共有组M（ConM）序列并用SOSIP稳定化突变工程化的Env三聚体融合到每个纳米颗粒的基础三聚体构建块。初步筛选产生了一个二十面体和两个四面体纳米颗粒候选物，能够呈现Env三聚体的二十或四个拷贝。许多分析，包括通过冷冻-EM的详细结构表征，证明纳米颗粒免疫原具有预期的结构和抗原特性。当ConM-SOSIP三聚体的免疫原性上提出的两个组件四面体纳米颗粒或可溶性蛋白质进行了比较，在兔子，两种免疫原引起了类似的血清抗体结合效价的三聚体组件。在给予纳米颗粒免疫原的动物中，中和抗体滴度略微升高，并且最初更集中于三聚体顶点。总之，我们的研究结果表明，四面体纳米粒子可以成功地应用于介绍艾滋病病毒包膜三聚体免疫原，然而，最佳的实施，以不同的免疫策略仍有待determined.Author摘要蛋白质构建基于可溶性胞外域的艾滋病病毒糖蛋白（包膜）三聚体是目前许多艾滋病病毒疫苗平台的基础。多价抗原展示是一种应用于提高各种亚单位疫苗候选物的免疫原性的策略。在这里，我们描述并全面评估了一个库的de novodesigned蛋白质纳米粒子的不同几何形状的能力，目前三聚体Env抗原。我们发现了三种纳米颗粒候选物，它们可以稳定地将模型Env三聚体结合在其表面上，同时保持结构和抗原性。所设计的纳米颗粒免疫原具有增加的刺激表达抗原特异性受体的B细胞的能力。在兔中评估一种纳米颗粒候选物的免疫原性。纳米颗粒呈现几何形状似乎改变了针对不同表位的抗体应答的分布，同时诱导相似的血清结合滴度和仅略微升高的中和滴度。除了介绍一套新的试剂多价展示Env三聚体，这项工作提供了指导原则和详细的实验路线图的生成，表征和优化Env呈递，自组装纳米颗粒免疫原。
Two-component, self-assembling nanoparticles represent a versatile platform for multivalent presentation of viral antigens. Computational design of protein nanoparticles with differing sizes and geometries enables combination with antigens of choice to test novel multimerization concepts in immunization strategies where the goal is to improve the induction and maturation of neutralizing antibody lineages. Here, we describe detailed antigenic, structural, and functional characterization of computationally designed tetrahedral, octahedral, and icosahedral nanoparticle immunogens displaying trimeric HIV envelope glycoprotein (Env) ectodomains. Env trimers, based on subtype A (BG505) or consensus group M (ConM) sequences and engineered with SOSIP stabilizing mutations, were fused to an underlying trimeric building block of each nanoparticle. Initial screening yielded one icosahedral and two tetrahedral nanoparticle candidates, capable of presenting twenty or four copies of the Env trimer. A number of analyses, including detailed structural characterization by cryo-EM, demonstrated that the nanoparticle immunogens possessed the intended structural and antigenic properties. When the immunogenicity of ConM-SOSIP trimers presented on a two-component tetrahedral nanoparticle or as soluble proteins were compared in rabbits, the two immunogens elicited similar serum antibody binding titers against the trimer component. Neutralizing antibody titers were slightly elevated in the animals given the nanoparticle immunogen and were initially more focused to the trimer apex. Altogether, our findings indicate that tetrahedral nanoparticles can be successfully applied for presentation of HIV Env trimer immunogens; however, the optimal implementation to different immunization strategies remains to be determined.Author summary Protein constructs based on soluble ectodomains of HIV glycoprotein (Env) trimers are the basis of many current HIV vaccine platforms. Multivalent antigen display is one strategy applied to improve the immunogenicity of various subunit vaccine candidates. Here, we describe and comprehensively evaluate a library ofde novodesigned protein nanoparticles of different geometries for their ability to present trimeric Env antigens. We found three nanoparticle candidates that can stably incorporate model Env trimers on their surfaces while maintaining structure and antigenicity. The designed nanoparticle immunogens had an increased capacity to stimulate B-cells expressing antigen-specific receptors. The immunogenicity of one nanoparticle candidate was assessed in rabbits. Nanoparticle presentation geometry appeared to alter the distribution of antibody responses against different epitopes while inducing similar serum binding titers and only slightly elevated neutralizing titers. In addition to introducing a novel set of reagents for multivalent display of Env trimers, this work provides both guiding principles and a detailed experimental roadmap for the generation, characterization, and optimization of Env-presenting, self-assembling nanoparticle immunogens.