RNA-based multi-antigen vaccine for SARS-CoV-2

项目概要/摘要（30行） 该提案旨在开发一种基于RNA的多抗原SARS-CoV-2疫苗，支持NIAID开发 使用新的抗原设计策略和新的递送方法的疫苗。SARS-CoV-2大流行 正在积极威胁公众健康、世界经济和生活方式。候选疫苗正在进行人体试验 但长期的解决方案将需要一个适应性强的疫苗系统，可以广泛普及到所有人 冠状病毒家族的成员。Tiba的疫苗将在两个方面具有创新性：1）包含所有四种 结构病毒体蛋白将允许针对冠状病毒的更深入和潜在更广泛的免疫反应， 疫苗将呈递多个保守的T细胞表位。此外，结构化的 除了刺突（S）蛋白之外的蛋白质将允许原位形成免疫原性VLP。2)常规脂质 纳米颗粒（LNP），其是核酸递送的主要部分，需要大比例的"结构"修饰。 脂质，导致RNA含量相对较低。Tiba开发了一种改良的树枝状聚合物递送分子， 使RNA质量含量最大化，保护RNA免于降解，并使细胞能够有效摄取。这 这种方法将增加免疫原性，从而提高疫苗的有效性。第一阶段的目标是优化 候选有效载荷包含M、N和E mRNA或saRNA。编码M、N和E的常规mRNA 蛋白质将经过密码子优化，然后将用Tiba的修饰树枝状聚合物配制先导RNA有效负载 送货材料。通过以saRNA和mRNA形式生成的M、N和E有效载荷， 每种的免疫原性剂量将通过用纳米颗粒注射六周龄BALB/c小鼠来确定， 不同的剂量用于滴定成S RNA疫苗候选物的抗原RNA有效载荷将是 选定.每种M、N和E mRNA或saRNA的最小有效剂量将使用 回归模型目标2将在小鼠中测试先导候选有效载荷沿着S。组合制剂 其中不同质量的前导M、N和E RNA被滴定到最佳S mRNA中， 或saRNA配方，以鉴定使M、N和E细胞免疫应答最大化，同时 而不是抑制S体液反应。治疗剂量将在所有受试者中递送相同质量的S RNA。 将根据初步剂量探索研究的结果选择最佳质量。使用 研究结果表明，两种混合物对每种病毒体组分产生可检测的反应，而对每种病毒体组分不产生可检测的反应。 抑制S抗体和T细胞应答的抗体将被选为主要候选者。对于目标3，主要候选人 将用于仓鼠激发研究。疫苗接种将在上午进行。注射在金色叙利亚 仓鼠将使用当前最佳实践进行挑战。本研究成功的基准是 是针对疫苗的S组分的免疫应答以及伴随的保护的证据 最好是在单次给药后。如果成功，进一步开发先导疫苗 候选人和商业化的途径将在第二阶段SBIR提案中公布。

Project Summary/Abstract (30 lines) The proposal is to develop an RNA-based multi-antigen SARS-CoV-2 vaccine, supporting NIAID’s call to develop a vaccine using emerging antigen design strategies and novel delivery approaches. The SARS-CoV-2 pandemic is actively threatening public health, world economies, and ways of life. Vaccine candidates are in human trials now, but long-term solutions will require an adaptable vaccine system that can be universalized broadly to all members of the coronavirus family. Tiba’s vaccine will be innovative in two respects: 1) The inclusion of all four structural virion proteins will allow a deeper and potentially broader immune response against coronavirus, as multiple conserved T cell epitopes will be presented by the vaccine. In addition, the incorporation of structural proteins besides the Spike (S) protein will allow the formation of immunogenic VLPs in situ. 2) Conventional lipid nanoparticles (LNPs), which are the mainstay of nucleic acid delivery, require a large proportion of “structural” lipid, resulting in a relatively low RNA content. Tiba has developed a modified dendrimer delivery molecule that maximizes RNA mass content, protects RNA from degradation, and enables efficient uptake by cells. This approach will increase immunogenicity and thus effectiveness of the vaccine. The first Phase 1 Aim is to optimize candidate payloads comprising M, N, and E mRNA or saRNA. Conventional mRNAs encoding the M, N, and E proteins will be codon-optimized and lead RNA payloads will then be formulated with Tiba’s modified dendrimer delivery material. With the M, N, and E payloads generated in both saRNA and mRNA formats, effective immunogenic doses for each will be determined by injecting six-week-old BALB/c mice with nanoparticles at different doses. The antigen RNA payloads to proceed for titration into S RNA vaccine candidates will be selected. The minimum effective dose for each M, N, and E mRNA or saRNA will be roughly estimated using a regression model. Aim 2 will test the lead candidate payloads along with S in mice. Combination formulations will be generated wherein different masses of the lead M, N, and E RNAs are titrated into the optimal S mRNA or saRNA formula to identify a formulation mixture that maximizes M, N, and E cellular immune responses while not suppressing the S humoral response. Treatment doses will deliver the same mass of S RNA across all groups, and that optimal mass will be chosen based on the results of dose-finding preliminary studies. Using the results of the study, two mixtures that confer detectable responses against each virion component while not suppressing S antibody and T cell responses will be selected as lead candidates. For Aim 3, the lead candidates will be used in a hamster challenge study. Vaccinations will be performed by i.m. injection in golden Syrian hamsters. Challenges will be performed using the current best practice. The benchmark of success for this study is evidence of immune responses against firstly the S component of the vaccine, and concomitant protection against disease, ideally after a single administration. If successful, further development of lead vaccine candidates and the path to commercialization will be forthcoming in a Phase 2 SBIR Proposal.