Evaluation of iDMV-1.0: A Single Dose Self-Amplifying Vaccine for SARS-CoV-2

项目总结：Devdoot Majumdar博士，研究项目负责人（RPL） 针对SARS-CoV-2的mRNA疫苗被证明出乎意料地有效，但也需要一系列 加强免疫以保持保护性。这些疫苗的全球部署一直很缓慢，特别是在 低收入和中等收入国家（LMIC），部分原因是与多个 接种疫苗因此，我们提出了一种新的RNA疫苗设计：单剂量自扩增mRNA疫苗 基于SARS-CoV-2冠状病毒。我们的长期目标是开发一种新的疫苗形式， 由一种RNA疫苗组成，该疫苗可在一种免疫系统中对SARS-CoV-2提供持久的体液和细胞免疫， 单剂量。我们的新设计，命名为iDMV-1.0，利用RNA编码冠状病毒复制机制 以在双膜囊泡（DMV）内产生刺突mRNA。iDMV-1.0，一种20 kB RNA衍生物 来自SARS-CoV-2基因组，由SARS-CoV-2的NSP 1 -16组成，突变以稳定融合前 刺突蛋白（19）、ORF 6 -10、M蛋白和N蛋白、GFP和荧光素酶的构象，用于检测，和 SARS-CoV-2基因组的所有非编码5 ′和3 ′序列。因为iDMV-1.0允许自我放大 这种脂质纳米颗粒包封的RNA疫苗在Spike mRNA中表现出增加的蛋白质表达， 组织培养系统与单轮mRNA对照相比。 该资助的目的是评估iDMV-1.0在小鼠临床前研究中的应用。在目标1中，体液免疫 将通过评估iDMV-1.0与mRNA-1273相比的表位选择来研究对疫苗的应答 （Moderna SARS-CoV-2 mRNA疫苗）进行了研究。我们将 评估iDMV-1.0抗原表达的持久性和体液免疫应答的持久性， 在小鼠中进行常规mRNA疫苗接种。在目标2中，将比较 这两种疫苗模式，以确定是否产生了对SARS-CoV-2蛋白质组特异性的T细胞， iDMV-1.0。总之，这些研究将为了解一种药物的耐久性和特异性提供基础。 潜在的单次注射SARS-CoV-2 mRNA疫苗，提供了一个范例，可能有助于更大的疫苗 特别是在低收入国家的环境中。

PROJECT SUMMARY: Devdoot Majumdar, PhD, Research Project Leader (RPL) The mRNA vaccines against SARS-CoV-2 proved unexpectedly efficacious, but also require a series of booster immunizations to remain protective. Global deployment of these vaccines has been slow, particularly in low- and middle-income countries (LMIC), in part due to the logistical complications associated with multiple vaccinations. We therefore propose a new RNA vaccine design: a single-dose self-amplifying mRNA vaccine based on the SARS-CoV-2 coronavirus. Our long-term goal is to develop of a novel vaccine modality that consists of an RNA vaccine that feasibly delivers durable humoral and cellular immunity to SARS-CoV-2 in a single dose. Our novel design, named iDMV-1.0, utilizes RNA encoding the coronavirus replication machinery in order to produce Spike mRNA within double membrane vesicles (DMV). iDMV-1.0, a 20 kB RNA derived from the SARS-CoV-2 genome, consists of NSP1-16 of SARS CoV-2, mutations to stabilize the prefusion conformation of Spike protein (19), ORF6-10, M protein, and N protein, GFP and Luciferase for detection, and all non-coding 5’ and 3’ sequences of the SARS-CoV-2 genome. Because iDMV-1.0 permits self-amplification of Spike mRNA, this lipid nanoparticles-encapsulated RNA vaccine exhibits increased protein expression in tissue culture systems as compared to single round mRNA controls. The objective of this grant is to assess iDMV-1.0 in preclinical studies in mice. In Aim 1, the humoral immune response to the vaccine will be studied by assessing epitope choice of iDMV-1.0 as compared to mRNA-1273 (Moderna SARS-CoV-2 mRNA vaccine) using deep mutational scanning and traditional serology. We will assess durability of antigen expression and durability of humoral immune response for iDMV-1.0 as compared to conventional mRNA vaccination in mice. In Aim 2, the cellular immune response will be compared between both vaccine modalities to determine whether T cells specific to the SARS-CoV-2 proteome are generated by iDMV-1.0. Together, these studies will provide the foundation to understand durability and specificity of a potential single-shot SARS-CoV-2 mRNA vaccine, providing a paradigm that may facilitate greater vaccine uptake, particularly in LMIC settings.