Lipid-Enveloped Nanoparticle Vaccines for HIV Neutralizing Antibody Generation

用HIV Spike蛋白免疫可引起主要针对天然HIV gpl20/41三聚体中的可变表位的抗体反应，几乎没有广泛的中和特异性。然而，一些广谱中和抗体识别gp41融合蛋白的高度保守的膜近端外区(MPER)。为了诱导针对gp41这一保守片段的抗体反应，我们提出了一种基于MPER多肽与“脂膜纳米粒”(NPs)的关联的策略， 病毒粒子大小的合成纳米粒子，具有可生物吸收的聚合物或水核和脂质表层。这种方法的动机是初步数据显示了与脂膜相关的MPER多肽的结构，这些多肽假定为广谱中和抗体(BNab)4E10所识别的构象。 这些颗粒的核心可用于提供T辅助表位的联合递送，而MPER多肽和TLR配体则从脂质颗粒表面呈现。具体目标是：(1)我们将根据颗粒表面脂组成和MPER多肽锚定确定识别bNab的最佳MPER呈现方式。(2)我们将测试将T辅助表位包裹在NPs的核心是否可以支持产生有助于抗体反应的CD4+T细胞，而不会误导抗体 反应远离颗粒表面显示的MPER多肽。(3)我们将分析TLR配体掺入颗粒表面对树突状细胞、B细胞和辅助性T细胞激活的影响以及由此产生的对MPER多肽的抗体反应，并测试NPs作为辅助佐剂递送腺苷能信号抑制物的能力。总之，这些策略将被用来产生一种引起bNab反应的艾滋病毒疫苗，并与项目1合作分析小鼠的体内反应。这一独特的 创造艾滋病毒疫苗的结构方法寻求将有关艾滋病毒保守残留物的关键结构信息与基于纳米颗粒的递送策略相结合，以实现能够广泛预防的中和抗体反应。

Immunization with HIV spike proteins elicits antibody responses directed largely against variable epitopes in the native HIV gpl20/41 trimer with little, if any broad neutralizing specificity. However, several broadly neutralizing antibodies recognize the highly conserved Membrane-Proximal External Region (MPER) of the gp41 fusion protein. To elicit antibody responses focused against this conserved fragment of gp41, we propose a strategy based on the association of MPER peptides with 'lipid-enveloped nanoparticles' (NPs), virion-sized synthetic nanoparticles with a bioresorbable polymer or aqueous core and lipid surface layer. This approach is motivated by preliminary data showing the structure of MPER peptides associated with lipid membranes, which assume a conformation recognized by the broadly neutralizing antibody (BNAb) 4E10. The core of these particles can be used to provide co-delivery of T-helper epitopes, while MPER peptides and TLR ligands are presented from the lipid particle surface. The specific aims are: (1) We will determine optimal MPER presentation for BNAb recognition in terms of particle surface lipid composition and MPER peptide anchoring. (2) We will test whether encapsulation of T helper epitopes in the core of NPs can support the generation of CD4+ T cell help for antibody responses without misdirecting the antibody response away from the particle surface-diplayed MPER peptide. (3) We will analyze the impact of TLR ligand incorporation into particle surfaces, to adjuvant dendritic cell, B-cell, and helper T-cell activation and resulting antibody responses to MPER peptides, and test the ability of NPs to deliver adenosinergic signaling inhibitors as co-adjuvants. Together, these strategies will be used to generate an HIV vaccine that elicits BNAb responses, with in vivo responses in mice analyzed in collaboration with Project 1. This unique structural approach to creation of an HIV vaccine seeks to combine key structural information about conserved residues of the HIV virus with a nanoparticle-base delivery strategy to achieve a neutralizing antibody response capable of broad prophylactic protection.