B cell TLRs and germinal centers

 性状（由申请方提供）：体液免疫应答质量的决定因素，包括产生的抗体的大小和同种型，以及亲和力成熟的程度，仍然定义不清，限制了合理疫苗设计的努力。尽管早期的研究已经涉及在快速的低亲和力抗体应答中由B细胞的Toll样受体（TLR）进行的先天免疫识别，但是我们最近的研究已经表明由B细胞的TLR 9或TLR 7进行的先天识别强烈地增强了生发中心（GC）应答的幅度和功效，这产生了高质量的抗体。此外，TLR的这种新功能已被证明是小鼠模型中针对几种病毒感染的免疫防御所必需的。此外，越来越多的证据表明，TLR 7和TLR 9是在系统性红斑狼疮（SLE）小鼠模型中产生抗核抗体所需的关键组分。因此，TLR促进高亲和力GC抗体应答的新途径可能对于针对许多病毒的免疫防御和SLE的发展是重要的。 最近的研究已经开始定义TLR识别增强IgG应答的幅度和质量的细胞基础，但是这种调节的分子机制是未知的，这是本申请的主题。具体目标1旨在定义与响应相同免疫但缺乏TLR信号传导组分MyD 88的功能性版本的GC B细胞相比，经历通过其TLR 9刺激的GC B细胞中mRNA和微小RNA表达的变化。具体目标2将解决基因表达的关键变化集中在GC B细胞亚群中的假设，即接收来自滤泡辅助T细胞（TFH）的选择信号和/或对抗原具有较高亲和力的GC B细胞。将通过对来自表达Myc-GFP报告基因（由与TFH细胞的有效相互作用产生）的GC B细胞或来自对抗原具有确定亲和力的GC B细胞的基因表达谱进行微流体单细胞分析来评估该问题。了解这一过程的分子机制将有助于合理的疫苗设计，也为开发治疗SLE的疗法提供了新的靶点。

 DESCRIPTION (provided by applicant): Determinants of the quality of a humoral immune response, including the magnitude and isotype of antibody produced, and the extent of affinity maturation, remain poorly defined, limiting efforts of rational vaccine design. Whereas earlier studies had implicated innate immune recognition by Toll-like receptors (TLRs) of B cells in rapid lower affinity antibody responses, our recent studies have shown that innate recognition by TLR9 or TLR7 of B cells strongly enhances the magnitude and the efficacy of the germinal center (GC) response, which generates high quality antibodies. Moreover, this novel function of TLRs has been shown to be required for immune defense against several virus infections in mouse models. In addition, accumulating evidence has indicated that TLR7 and TLR9 are critical components required for the production of anti-nuclear antibodies in mouse models of systemic lupus erythematosus (SLE). Thus, a new pathway whereby TLRs promote high affinity GC antibody responses is likely to be important for immune defense against many viruses and for development of SLE. Recent studies have begun to define the cellular basis by which TLR recognition enhances the magnitude and quality of the IgG response, but the molecular mechanisms underlying this regulation are unknown, which is the topic of this application. Specific Aim 1 is designed to define the changes in mRNA and microRNA expression in GC B cells experiencing stimulation via their TLR9 compared to GC B cells responding to the same immunization but lacking a functional version of the TLR signaling component MyD88. Specific Aim 2 will address the hypothesis that key changes in gene expression are concentrated in subsets of GC B cells, namely GC B cells that are receiving selection signals from follicular helper T cells (TFH) and/or have a higher affinity for antigen. This issue will be assessed by microfluidic single cell analysis of gene expression profiles from GC B cells expressing a Myc-GFP reporter (resulting from productive interaction with TFH cells) or from GC B cells of defined affinity for antigen. Understanding the molecular mechanisms of this process will be useful for rational vaccine design and also many provide new targets for development of therapies to treat SLE.