Engineered lipid vesicles as potent vaccine vectors for HIV

描述（由申请人提供）：成功接种HIV疫苗可能需要产生协调的体液和细胞免疫。在目前的策略中，蛋白质疫苗不能刺激细胞反应，而能够促进细胞和体液反应的质粒DNA或活重组载体同时面临其他问题，例如在人体内的效力（DNA），或载体特异性免疫和/或安全性的挑战（活载体）。我们在这里提出了一类新的用于蛋白质疫苗递送的基于脂质的囊泡，它由多层脂质囊泡组成，通过引入连接双层结构的交联来稳定。这些新材料是在温和的全水过程中合成并包封蛋白抗原的，有利于保存复杂抗原上的表位。在初步研究中，我们发现这些新型疫苗载体可以重复进行同源增强：在用模型抗原进行一次初级和两次加强免疫后，这些颗粒大量扩增抗原特异性CD8+ t细胞，据我们所知，这比之前报道的任何蛋白质疫苗都要强得多。这些t细胞在产生IFN-？在第二次提升一个月后形成了大量的记忆群。在其他初步研究中，我们发现这个系统驱动针对候选疟疾抗原的有效体液反应。基于这些有希望的初步结果，我们建议在HIV疫苗接种的背景下测试这种新的疫苗递送方法的前景，旨在确定是否可以引发针对HIV gag和env抗原的有效，持久的t细胞和体液反应。此外，我们将探索是否可以利用该疫苗系统的特定方面（例如，颗粒在注射部位的沉积）来指导记忆细胞定位到关键的粘膜组织部位，从而促进对HIV感染的保护。我们的具体目标是：(1)ICMV颗粒疫苗对gag和env抗原的体液和细胞反应是如何随着抗原剂量和增强而进化的？(2)替代临床相关的TLR激动剂/危险信号在ICMV载体传递时是否能够引发比MPLA更强的免疫反应？(3)与传统的蛋白质免疫相比，ICMV颗粒免疫后，在注射部位保留的颗粒如何影响记忆/效应细胞的运输？(4)是否可以使用微针输送来重复进行无针颗粒增强，而不需要冷藏疫苗？鉴定出能够提高对HIV免疫原的免疫应答的ICMV配方，与我们对OVA或疟疾抗原的初步数据显示的免疫应答相当，将为随后在猕猴保护模型中进行试验奠定基础（要么单独接种ICMV疫苗，要么与其他强效HIV候选疫苗联合接种）。

DESCRIPTION (provided by applicant): Successful vaccination against HIV will likely require the generation of coordinated humoral and cellular immunity. Among current strategies, protein vaccines fail to stimulate cellular responses, while plasmid DNA or live recombinant vectors capable of promoting cellular and humoral responses together face other issues, such as potency in humans (DNA), or challenges of vector-specific immunity and/or safety (live vectors). We propose here a new class of lipid-based vesicles for protein vaccine delivery, composed of multilamellar lipid vesicles stabilized by the introduction of crosslinks connecting the bilayers of the structure. These novel materials are synthesized and encapsulate protein antigens in a mild all-aqueous process, favoring the preservation of epitopes on complex antigens. In preliminary studies, we show that these novel vaccine carriers can be repeatedly administered for homologous boosting: Following a prime and 2 booster immunizations with a model antigen, these particles massively expand antigen-specific CD8+ T-cells, to the best of our knowledge substantially stronger than any previously reported protein vaccine. These T-cells were functional in terms of their capacity to produce IFN-?, and formed a substantial memory population a month after the second boost. In other preliminary studies, we found that this same system drives potent humoral responses against a candidate malaria antigen. Based on these promising initial results, we propose here to test the promise of this new vaccine delivery approach in the context of HIV vaccination, aiming to determine whether potent, durable T-cell and humoral responses can be elicited against HIV gag and env antigens. In addition, we will explore whether particular aspects of this vaccine system (e.g., the deposition of particles at the injection site) can be exploited to direct the localization of memory cells to key mucosal tissue sites that could promote protection against HIV infection. Our specific aims are: (1) How do the humoral and cellular responses to gag and env antigens evolve as a function of antigen dose and boosting with ICMV particle vaccination? (2) Are alternative clinically-relevant TLR agonist/danger signals capable of eliciting stronger immune responses than MPLA when delivered by ICMV vectors? (3) How do particles retained at the injection site influence memory/effector cell trafficking following ICMV particle immunization, compared to traditional protein immunization? (4) Can microneedle delivery be used to allow repeated needle-free particle boosting to be performed, without the need for refrigerated vaccines? Identification of ICMV formulations that can raise immune responses against HIV immunogens comparable to those shown in our preliminary data for OVA or malaria antigens will set the stage for subsequent testing in macaque protection models (either using ICMV vaccination alone or in tandem with other strong HIV vaccine candidates. PUBLIC HEALTH RELEVANCE: In this application, we propose research aimed at testing the promise of a new class of lipid-based nanoparticles for vaccination against HIV. These studies will shed important new light on the mechanisms of immune stimulation by this nanoparticle vaccine, and if successful, these materials will provide a powerful hew vaccine complementary to existing platforms being tested in the effort to develop a protective AIDS vaccine.