Shielding Replicating Single-cycle Vaccines against SARS-CoV-2

屏蔽针对 SARS-CoV-2 的复制单周期疫苗

• 批准号: 10884592
• 负责人: Michael A Barry
• 金额: $ 47.06万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-17 至 2024-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10884592
• 关键词: 2019-nCoV; Adenovirus Infections; Adenoviruses; Affect; Affinity; Animal Model; Animals; Antibodies; Antigens; Benchmarking; Binding; Biology; Blood; Blood Coagulation Factor; Blood Proteins; Blood coagulation; Body Weight; COVID-19; COVID-19 vaccination; COVID-19 vaccine; Cells; Chemical Engineering; Chemicals; Complementarity Determining Regions; Complex; Cryoelectron Microscopy; DNA; DNA biosynthesis; Dose; Engineering; Future; Genes; Genetic; Genetic Engineering; Hamsters; Human; Immune response; Immunization; Lung; Messenger RNA; Production; Proteins; RNA vaccine; Resolution; Risk; Safety; Serotyping; Structure; Testing; Thrombocytopenia; Transgenes; Translating; Vaccination; Vaccine Antigen; Vaccines; Viral Load result; Virion; Virus; gene therapy; in vivo; neutralizing antibody; oncolytic adenovirus; pathogen; permissiveness; preservation; prevent; risk mitigation; side effect; thrombotic; vaccine delivery; vaccine efficacy; vaccine safety; vaccine trial; vector

Abstract Many COVID-19 vaccines are replication-defective mRNA, DNA, or adenovirus (Ad) vaccines. In each case, the vaccine delivers its one copy of an antigen gene and expresses "1X" of the antigens that are encoded by the vaccine. We developed single cycle Ad (SC-Ad) vaccines that replicate vaccine antigen genes up to 10,000-fold in every cell to amplify antigen production but do not produce infectious progeny viruses. When RD-Ad and SC- Ad6 expressing SARS-CoV-2 are compared, SC-Ad produces 100 times more spike protein than RD-Ad and significantly higher spike antibodies than RD-Ad-Spike. When the animals were challenged 10.5 months after single immunization, SC-Ad reduced SARS-CoV-2 lung viral loads and damage and preserved body weights better than RD-Ad. However, observations of vaccine-induced thrombotic thrombocytopenia (VITT) in Ad26 and ChAdOx-1 COVID-19 vaccine trials endanger the prospects of SC-Ad and all other adenovirus vaccines. In one hypothesis, VITT is thought to be caused by the binding of PF4 to the hexons of Ad26 and ChAdOx-1. This complex is thought to provoke antibodies against PF4 that cause VITT. While VITT could theoretically occur with any adenovirus, the particular serotype of each Ad may influence the risk of this side effect. Different Ad serotypes vary in the hypervariable regions (HVRs) of their hexon proteins. These HVRs determine whether the antibodies and other proteins like PF4 bind or do not bind each adenovirus. We hypothesize that the natural binding of blood proteins to species C Ads may naturally shield them from PF4 binding whereas other serotypes are at risk of PF4 binding. One can also genetically and chemically engineer Ads to proactively shield them from interactions with antibodies and PF4. We hypothesize that genetic and chemical shielding can be used to make safer SC-Ad and other Ads for vaccination against SARS-CoV-2 and other pathogens. This project will test these hypotheses in three Specific Aims. In the first, we will perform high resolution cryo- electron microscopy to examine the interactions of PF4 and other proteins on species C and species D adenoviruses. In the second aim, we will compare the utility of genetic and chemical shielding strategies to protect Ads from PF4 and also against neutralizing antibodies. In the third aim, we will test if different Ad serotypes bound to PF4 can provoke VITT in animal models, whether this is different for different serotypes, and whether genetic and chemical shielding can maintain vaccine efficacy while mitigating the risks of VITT induction. Successful pursuit of this project will lead to better understanding of natural binding of blood clotting factors to different serotypes and how this affects their in vivo biology and side effects. This project will also test and optimize proactive strategy to increase adenovirus vaccine safety for SARS-CoV-2 and future pathogen targets. This can have utility for vaccines, gene therapy, or oncolytic adenoviruses to increase efficacy and safety and protect them from not only PF4, but also against problematic vector neutralizing antibodies.

抽象的 许多COVID-19疫苗是复制缺陷的mRNA，DNA或腺病毒（AD）疫苗。在每种情况下， 疫苗提供其一份抗原基因的副本，并表示由抗原的“ 1x” 疫苗。我们开发了单个周期AD（SC-AD）疫苗，该疫苗复制疫苗抗原基因最多10,000倍 在每个细胞中，可以扩增抗原产生，但不会产生感染性后代病毒。当RD-AD和SC- 比较了表达SARS-COV-2的AD6，SC-AD产生的峰值蛋白比RD-AD高100倍，并且 尖峰抗体明显高于RD-AD尖峰。当动物在10.5个月后受到挑战时 单个免疫，SC-AD降低SARS-COV-2肺病毒载荷和损伤以及保留的体重 比RD-AD好。但是，在AD26和 Chadox-1 Covid-19疫苗试验危害SC-AD和所有其他腺病毒疫苗的前景。一个 假设，VITT被认为是由PF4与AD26和Chadox-1的Hexon的结合引起的。这 人们认为复合物会引起对造成Vitt的PF4的抗体。理论上可以发生维特 任何腺病毒，每个广告的特殊血清型都可能影响这种副作用的风险。不同的广告 血清型在其己酮蛋白的高变量区域（HVR）中有所不同。这些HVR决定了是否 抗体和其他蛋白质（如PF4）结合或不结合每个腺病毒。我们假设自然 血液蛋白与物种C AD的结合自然可能会使它们免受PF4结合的影响，而其他血清型 有PF4结合的风险。一个人也可以在遗传和化学工程师的广告上主动保护它们免受 与抗体和PF4的相互作用。我们假设遗传和化学屏蔽可用于使 更安全的SC-AD和其他广告，用于针对SARS-COV-2和其他病原体的疫苗接种。 该项目将以三个特定目标来检验这些假设。首先，我们将执行高分辨率的冷冻 电子显微镜检查PF4和其他蛋白质在物种C和物种D上的相互作用 腺病毒。在第二个目标中，我们将将遗传和化学屏蔽策略的效用与 保护AD免受PF4的影响，并免受中和抗体的影响。在第三个目标中，我们将测试是否不同的广告 与PF4绑定的血清型可以在动物模型中引起VITT，这是否不同于不同的血清型和 遗传和化学屏蔽是否可以在减轻VITT诱导风险的同时保持疫苗功效。 成功追求该项目将使对血液凝结因素的自然结合更好地了解 不同的血清型以及这如何影响其体内生物学和副作用。该项目还将测试 优化主动策略，以增加SARS-COV-2和未来病原体靶标的腺病毒疫苗安全性。 这可以具有用于疫苗，基因疗法或溶瘤腺病毒的效用，以提高功效和安全性和 不仅可以保护它们免受PF4的侵害，还可以免受有问题的载体中和抗体。