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 疫苗是复制缺陷型 mRNA、DNA 或腺病毒 (Ad) 疫苗。在每种情况下， 疫苗递送其抗原基因的一份拷贝并表达由该疫苗编码的“1X”抗原 疫苗。我们开发了单周期 Ad (SC-Ad) 疫苗，可复制疫苗抗原基因高达 10,000 倍 在每个细胞中放大抗原的产生，但不产生传染性子代病毒。当 RD-Ad 和 SC- 比较表达 SARS-CoV-2 的 Ad6，SC-Ad 产生的刺突蛋白比 RD-Ad 多 100 倍， 刺突抗体明显高于 RD-Ad-Spike。当动物在 10.5 个月后受到挑战时 单次免疫，SC-Ad 减少了 SARS-CoV-2 肺部病毒载量和损伤，并保持了体重 比 RD-Ad 更好。然而，Ad26 和 Ad26 中疫苗诱导的血栓性血小板减少症 (VITT) 的观察结果 ChAdOx-1 COVID-19 疫苗试验危及 SC-Ad 和所有其他腺病毒疫苗的前景。合而为一 根据假设，VITT 被认为是由 PF4 与 Ad26 和 ChAdOx-1 的六邻体结合引起的。这 该复合物被认为会激发针对 PF4 的抗体，从而导致 VITT。虽然 VITT 理论上可能发生 对于任何腺病毒，每种腺病毒的特定血清型可能会影响这种副作用的风险。不同的广告 血清型的六邻体蛋白高变区（HVR）各不相同。这些 HVR 决定是否 抗体和其他蛋白质（如 PF4）结合或不结合每种腺病毒。我们假设自然 血液蛋白与 C 种广告的结合可以自然地保护它们免受 PF4 结合，而其他血清型 存在 PF4 结合的风险。人们还可以对广告进行基因和化学工程，以主动屏蔽它们 与抗体和 PF4 的相互作用。我们假设遗传和化学屏蔽可以用来制造 更安全的 SC-Ad 和其他广告，用于针对 SARS-CoV-2 和其他病原体进行疫苗接种。 该项目将在三个具体目标中测试这些假设。首先，我们将进行高分辨率冷冻 使用电子显微镜检查 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，我们将比较遗传和化学屏蔽策略的效用 保护广告免受 PF4 和中和抗体的侵害。在第三个目标中，我们将测试是否有不同的广告 与 PF4 结合的血清型可以在动物模型中引起 VITT，无论不同血清型是否不同，以及 遗传和化学屏蔽是否可以维持疫苗功效，同时降低 VITT 诱导风险。 该项目的成功实施将有助于更好地了解凝血因子与凝血因子的自然结合。 不同的血清型以及这如何影响它们的体内生物学和副作用。该项目还将测试和 优化主动策略，提高 SARS-CoV-2 和未来病原体目标的腺病毒疫苗安全性。 这可用于疫苗、基因疗法或溶瘤腺病毒，以提高功效和安全性， 不仅可以保护它们免受 PF4 的侵害，还可以防止有问题的载体中和抗体的侵害。