Strength of TCR:self-pMHC interactions in the periphery instructs CD4+ T help cell responses

项目摘要 对于许多致命疾病，有效的疫苗仍然难以捉摸;因此，我们必须更好地了解如何 免疫系统对疫苗接种产生一种强有力的中和抗体反应， 在未来的疫苗设计中。B细胞是高亲和力抗体的生产者，然而， 提供驱动该B细胞命运所必需的细胞因子和共刺激分子的CD 4 + T细胞， 建立长期的体液免疫。这就是为什么我们必须更好地了解发展， 参与产生这种类型的反应的特定CD 4 + T细胞亚群的功能。原发性感染或 在接种疫苗后，一些活化的CD 4 + T细胞成为特异性已知提供直接B细胞的特化亚群， help：T滤泡辅助细胞（Tfh）。是什么使T细胞成为Tfh细胞的命运仍然是未知的。我们的新方法 利用针对B6小鼠中李斯特菌的免疫显性LLO表位的CD 4 + T细胞应答， 两个确定的CD 4 + TCR转基因系和多克隆T细胞。这两种初始T细胞的紧张性信号传导不同， 通过自身pMHC的TCR识别介导。具有低紧张性信号传导的初始CD 4 + T细胞具有高的免疫应答。 基础代谢，在主要体内应答中强烈应答，并发育成Tfh和TEM细胞。相反地， 具有高紧张性信号传导的初始CD 4 + T细胞具有低的基础代谢，并且难以形成Tfh细胞。前提 TCR的强度：自身pMHC反应性（紧张性信号传导）对于建立免疫应答是决定性的。 基础代谢和随后的Tfh反应。在目标1中，我们将确定是否存在直接关系 存在于紧张性信号传导和抗原暴露后Tfh的发展之间。为此，我们将使用 我们的新型敲入小鼠系Scn 5a+。Scn 5a电压门控钠通道的表达使我们能够 增加不依赖于TCR信号传导的CD 4 + T细胞中的紧张性信号传导。我们将使用一种 新开发的H-2DM的条件性敲除等位基因。将使用NP-LLO模型测试Tfh辅助功能。 在目标2中，我们将研究T细胞代谢如何影响Tfh细胞反应。我们已经鉴定了甘油 磷酸穿梭作为LLO-118 T细胞代谢增加的关键参与者。我们现在已经生成了 具有mGPD 2的条件性敲除等位基因的小鼠，这将是探索这一作用的有力试剂。 LLO-118和多克隆CD 4 + T细胞应答的代谢途径。这些发现将加深我们的 了解Tfh的发展，并可能揭示疫苗设计和自身免疫的治疗靶点。

PROJECT SUMMARY Effective vaccines remain elusive for many deadly diseases; therefore, it is critical that we better understand how the immune system generates a robust, neutralizing antibody response to vaccination so that we may enhance this type of response in future vaccine design. B cells are the producers of high-affinity antibodies, however, it is the CD4+ T cells that provide the cytokines and co-stimulatory molecules necessary to drive this B cell fate and establish long-term humoral immunity. This is why it is critical that we better understand the development and function of specific CD4+ T cell subsets involved in generating this type of response. After a primary infection or vaccination, some activated CD4+ T cells become a specialized subset specifically known to provide direct B cell help: T follicular helper (Tfh) cells. What commits T cells to the Tfh cell fate is still unknown. Our novel approach leverages the CD4+ T cell response against the immunodominant LLO epitope from Listeria in B6 mice, using two defined CD4+ TCR transgenic lines and polyclonal T cells. The two naive T cells differ in their tonic signaling mediated through the TCR recognition of self-pMHC. Naive CD4+ T cells with low tonic signaling have a high basal metabolism, respond robustly in a primary in vivo response, and develop into Tfh and TEM cells. Conversely, naive CD4+ T cells with high tonic signaling have a low basal metabolism, and poorly form Tfh cells. The premise of this proposal is that the strength of TCR:self-pMHC reactivity (tonic signaling) is deterministic for establishing the basal metabolism and the subsequent Tfh response. In Aim 1, we will establish whether a direct relationship exists between tonic signaling and the development of Tfh following antigen exposure. To this end, we will use our novel knock-in mouse line, Scn5a+. Expression of th Scn5a voltage gated sodium channel allows us to increase tonic signaling in CD4+ T cells independent of TCR signaling. We will decrease tonic signaling using a newly developed conditional knockout allele of H-2DM. Tfh helper function will be tested using an NP-LLO model. In Aim 2 we will examine how T cell metabolism influences Tfh cell responses. We have identified the glycerol phosphate shuttle as a key player in the increased metabolism of the LLO-118 T cells. We have now generated a mouse with a conditional knockout allele of mGPD2 which will be a powerful reagent to explore the role of this metabolic pathway in LLO-118 and polyclonal CD4+ T cell responses. These findings will deepen our understanding of Tfh development and may reveal therapeutic targets for vaccine design and autoimmunity.