mRNA as a mediator of immunological information transfer in vivo

mRNA 作为体内免疫信息传递的介质

基本信息

批准号：
8735569
负责人：
J. Lindsay Whitton
金额：
$ 28.43万
依托单位：
SCRIPPS RESEARCH INSTITUTE, THE
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-06-01 至 2016-05-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8735569
关键词：
Acute Antibodies Antiviral Agents Bacteria Bacterial Infections Biological CD4 Positive T Lymphocytes CD8B1 gene Cancer Vaccines Cells Characteristics Clinical Code Complex Cross Presentation Cross-Priming Data Dendritic Cells Disease Enterovirus Epitopes Goals Grant Human Immune Immune response Immunity Immunology In Vitro Infection Injection of therapeutic agent MHC Class I Genes Mediator of activation protein Messenger RNA Microbe Mus Names Nature Organism Paper Pathway interactions Peptides Play Process Proteins RNA Reading Recombinants Regulatory Element Role Signal Transduction Study Section Surface T cell response T-Lymphocyte Testing Transfer RNA Translating Translations Uncertainty Vaccination Vaccines Viral Viral Proteins Virus Virus Diseases Work Yeasts cell type extracellular high reward high risk in vivo innovation microbial pathogen public health relevance research study tumor vector vaccine

项目摘要

In vivo injection of mRNA triggers immune responses to the encoded proteins, and confers protection against disease. For this and other reasons, outlined below, RNA vaccines have great clinical potential, so it is important that we understand how they induce immunity. I hypothesize that RNA vaccines may be exploiting a cell type, and biological pathway, that have evolved specifically to capture, internalize, and translate mRNA. I propose that this pathway facilitates the transfer of immunological information into uninfected dendritic cells (DCs), thereby playing a key part in regulating CD8+ T cell responses to many viral and bacterial infections. Almost all acute virus infections induce strong CD8+ T cell responses, which are initiated when na¿ve CD8+ T cells are activated by contact with an MHC class I / epitope peptide complex on the surface of DCs that express appropriate costimulatory molecules. However, many viruses do not infect DCs; and some viruses that infect DCs also encode proteins that quite effectively inhibit MHC class I presentation. These facts posed a puzzle: how could epitopes encoded by these viruses be effectively presented by DCs? The answer came with the identification of cross-presentation which, if it results in the triggering of naive CD8+ T cells, causes cross-priming. However, two in vivo observations show that cross-presentation/cross-priming (hereinafter, CP) is not always highly-efficient. First, enteroviruses replicate to very high titers and induce CD4+ T cells and antibodies, yet (unique among acute virus infections) they completely avoid triggering na¿ve CD8+ T cells. Second, extracellular bacterial infections, in which microbial protein is hugely abundant, do not induce strong CD8+ T cell responses. For reasons described below, I hypothesize that both observations can be explained by proposing that some transfer of immunological information into uninfected DCs may rely on mRNA (rather than protein). So, this proposal has two goals: First, to evaluate how naked RNA induces immunity. Second, to test the hypothesis that, during most microbial infections, mRNA is transferred to uninfected DCs; if it is translated therein, the encoded protein will reach the class I MHC pathway, inducing strong CD8+ T cell responses; I have named this mechanism TATOR (transfer and translation of RNA). Conversely, if the mRNA cannot be translated, the organism is undetectable by CD8+ T cells. Thus, the specific characteristics of their mRNAs renders enteroviruses and extracellular bacteria invisible to CD8+ T cells. Aim 1. To identify and characterize the DC subset that is involved in RNA-triggered immunity. Aim 2. To determine if mRNA regulatory sequences explain why extracellular bacteria fail to induce strong CD8+ T cell responses.

体内注射 mRNA 会引发针对编码蛋白质的免疫反应，并提供保护由于这个原因和其他原因（如下所述），RNA 疫苗具有巨大的临床潜力，因此，了解它们如何诱导免疫力非常重要。利用专门进化来捕获、内化和我认为该途径有助于将免疫学信息转移到mRNA中。未感染的树突状细胞 (DC)，在调节 CD8+ T 细胞对许多疾病的反应中发挥着关键作用病毒和细菌感染几乎所有急性病毒感染都会引起强烈的 CD8+ T 细胞反应。当 na¿ 时启动ve CD8+ T 细胞通过与 MHC I 类/表位肽接触而被激活然而，DC 表面上表达适当的共刺激分子的复合体有很多。病毒不感染树突状细胞；并且一些感染树突状细胞的病毒也编码非常有效的蛋白质。这些事实提出了一个难题：这些表位如何编码？病毒能否被树突状细胞有效地呈递？答案来自于交叉呈递的鉴定。如果它导致初始 CD8+ T 细胞的触发，则会导致体内交叉启动。观察表明，交叉呈现/交叉启动（以下简称 CP）并不总是高效的。首先，肠道病毒复制到非常高的滴度并诱导 CD4+ T 细胞和抗体，但（独特的在急性病毒感染中）它们完全避免触发 na¿第二，细胞外的CD8+T细胞。细菌感染，其中微生物蛋白非常丰富，不会诱导强 CD8+ T 细胞由于下述原因，我认为这两个观察结果都可以解释为提出一些免疫信息转移到未感染的 DC 中可能依赖于 mRNA （而不是蛋白质）因此，该提案有两个目标：首先，评估裸RNA如何诱导。其次，检验以下假设：在大多数微生物感染期间，mRNA 会转移到免疫系统。未感染的 DC；如果在其中翻译，编码的蛋白质将到达 I 类 MHC 途径，诱导强烈的 CD8+ T 细胞反应；我将这种机制命名为 TATOR（转移和翻译） RNA），如果 mRNA 无法翻译，则 CD8+ T 细胞无法检测到该生物体。因此，它们的 mRNA 的特定特征使得肠道病毒和胞外细菌 CD8+ T 细胞不可见。目标 1. 鉴定和表征参与 RNA 触发免疫的 DC 亚群。目标 2. 确定 mRNA 调控序列是否可以解释为什么胞外细菌无法诱导强烈的 CD8+ T 细胞反应。