mRNA as a mediator of immunological information transfer in vivo

体内注射信使核糖核酸触发对编码蛋白的免疫反应，并提供保护 对抗疾病。由于下面概述的这一原因和其他原因，RNA疫苗具有巨大的临床潜力， 因此，重要的是我们要了解它们是如何诱导免疫的。我推测RNA疫苗可能是 利用一种细胞类型和生物途径，这些细胞和生物途径已经特别进化来捕获、内化和 翻译信使核糖核酸我认为这一途径有助于将免疫学信息转移到 未感染的树突状细胞(DC)，从而在调节CD8+T细胞对许多 病毒和细菌感染。几乎所有的急性病毒感染都会诱导强烈的CD8+T细胞反应， 当NAVE CD8+T细胞通过与MHC I类/表位多肽接触而被激活时， 树突状细胞表面的复合体，表达适当的共刺激分子。然而，许多人 病毒不会感染DC；一些感染DC的病毒也会编码非常有效的蛋白质 抑制MHC I类呈递。这些事实提出了一个难题：由这些基因编码的表位如何 DC会有效地呈现病毒吗？答案来自于对交叉呈现的识别 如果它导致幼稚的CD8+T细胞的触发，就会导致交叉激发。然而，体内有两个 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(独一无二 在急性病毒感染中)，它们完全避免触发原始CD8+T细胞。第二，细胞外 细菌感染，其中微生物蛋白非常丰富，不会诱导强大的CD8+T细胞 回应。出于下面描述的原因，我假设这两个观察结果都可以用 提出免疫信息向未受感染的DC的某些转移可能依赖于mRNA (而不是蛋白质)。因此，这项提议有两个目标：第一，评估裸RNA是如何诱导 豁免权。其次，为了检验这一假设，在大多数微生物感染期间，信使核糖核酸被转移到 未感染的DC；如果在其中翻译，编码的蛋白将到达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)。相反，如果信使核糖核酸不能被翻译，CD8+T细胞就无法检测到该生物体。 因此，它们的mRNAs的特殊特性使肠道病毒和胞外细菌 CD8+T细胞看不见。 目的1.鉴定和鉴定参与RNA触发免疫的DC亚群。 目的2.确定信使核糖核酸调控序列是否能解释为什么胞外细菌无法 诱导强烈的CD8+T细胞反应。

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.