Mechanisms of protective memory CD8 T-cell induction by mRNA-LNP vaccines

摘要 CD8T细胞识别和杀伤病毒感染的细胞，显示在细胞表面结合的短病毒多肽 主要组织相容性(MHC)I类分子(MHC-I)。CD8 T细胞有助于清除许多 病毒感染。感染消退后，扩大的“记忆”CD8T细胞群(M CD8T细胞) 可能有助于更快地控制病毒的继发感染。疫苗可以模拟这一过程。 脂质纳米粒包裹的修饰信使核糖核酸(mmRNA-LNP)已成为一种 强大的疫苗平台。MmRNALNPs作为疫苗有许多优点：1)它们可以集中在 感兴趣的抗原。2)它们具有高度的免疫原性。3)它们很容易制作。4)它们可以批量生产 迅速地。5)它们相对便宜。MmRNA-LNP疫苗的迅速开发和批准 抗击SARS-CoV-2证明了他们的潜力。虽然已知mmRNA-LNPs可诱导CD8 T细胞反应， 关于它们的保护机制的大部分工作都集中在抗体上。MmRNA-1诱导的mCD8 T细胞 LNP可以潜在地补充抗体保护，或者可能为以下病毒提供大部分保护 对抗体介导的控制无效。MmRNALNPs还可用于诱导CD8T细胞抗肿瘤。 我们已经发表了由mmRNA-LNPs诱导的mCD8 T细胞反应保护小鼠免受高度 致死性鼠痘，是一种由正痘病毒(OPV)皮疹病毒引起的小鼠全身性病毒性疾病 (ECTV)。ECTV是全身性病毒感染和可能感染OPV的杰出模型 人类，如根除的天花病毒(天花病毒)和猴痘病毒(MPXV)，最近 引发了一场大规模的疫情。在仍未发表的实验中，我们还发现，由迷你-T细胞诱导的M-CD8 T细胞 仅编码SARS病毒最小的、高度保守的CD8 T细胞表位VNFNFNGL的mmRNA疫苗- CoV-2 Spike蛋白保护野生型小鼠免受小鼠适应的SARS的致命呼吸道感染-- 冠状病毒-2株MA30，SARS-CoV-2和其他严重呼吸道感染的杰出模型。在这里我们 建议利用ECTV阐明mmRNALNPs诱导保护性mCD8T细胞的机制 系统性和MA30 SARS-CoV-2呼吸道感染小鼠模型。我们的具体目标是：a)具体目标1. 探讨mmRNALNP免疫后MHC-I抗原提呈的机制。B)具体目标2。 探讨I型干扰素和其他促炎细胞因子在保护M CD8 T细胞中的作用 MRNA-LNP疫苗接种后的发育。

Summary CD8 T-cells recognize and kill virus-infected cells displaying at the cell surface short viral peptides bound to major histocompatibility (MHC) class I molecules (MHC-I). CD8 T-cells contribute to the clearance of many viral infections. After an infection subsides, an expanded population of “memory” CD8 T-cells (M CD8 T-cells) may contribute to more rapidly controlling a secondary infection with the virus. Vaccines can mimic this process. Modified mRNA (mmRNA) encapsulated in lipid nanoparticles (mmRNA-LNP) have emerged as a powerful vaccine platform. mmRNA-LNPs have many advantages as vaccines: 1) They can be focused on the antigen of interest. 2) They are highly immunogenic. 3) they are easy to make. 4) They can be mass-produced rapidly. 5) They are relatively inexpensive. The swift development and approval of the mmRNA-LNP vaccines to combat SARS-CoV-2 attest to their potential. While it is known that mmRNA-LNPs induce CD8 T-cell responses, most of the work on their protection mechanisms has focused on Abs. The mCD8 T-cells induced by mmRNA- LNP can potentially complement Ab protection or may provide most of the protection for viruses that are refractory to Ab-mediated control. mmRNA-LNPs could also be used to induce CD8 T-cells against cancer. We have published that the mCD8 T-cell responses induced by mmRNA-LNPs protect mice from highly lethal mousepox, a systemic viral disease of the mouse caused by the Orthopoxvirus (OPV) ectromelia virus (ECTV). ECTV is an outstanding model for systemic viral infections in general and for OPVs that can infect humans, such as the eradicated variola virus (virus of smallpox) and for monkeypox virus (MPXV), which recently caused a major outbreak. In still unpublished experiments, we also found that M CD8 T-cells induced by a mini- mmRNA vaccine encoding for only the minimal, highly conserved CD8 T-cell epitope VNFNFNGL of the SARS- CoV-2 Spike protein protects wild-type mice from lethal respiratory infection with the mouse-adapted SARS- CoV-2 strain MA30, an outstanding model for SARS-CoV-2 and other grave respiratory infections. Here we propose elucidating the mechanisms whereby mmRNA-LNPs induce protective mCD8 T-cells using the ECTV systemic and the MA30 SARS-CoV-2 respiratory mouse models. Our Specific Aims are to: A) Specific Aim 1. Investigate the Mechanisms of MHC-I antigen presentation after mmRNA-LNP vaccination. B) Specific Aim 2. Investigate the roles of Type I interferon (IFN-I) and other proinflammatory cytokines in protective M CD8 T-cell development after mRNA-LNP vaccination.