Manipulation of Follicular Helper T Cells in Immunity and Autoimmunity

描述（由申请方提供）：CD 4 T细胞辅助对于次级淋巴器官（SLO）的生发中心（GC）中发生的B细胞产生抗体至关重要，该生发中心是免疫球蛋白（IG）亲和力成熟和同种型转换的位点。在GC中，T滤泡辅助细胞（Tfh）为B细胞提供存活和分化信号，包括CD 40配体（CD 40）、程序性死亡受体-1（PD-1）和IL-21，这些信号对于B细胞选择以及成熟为记忆B细胞和长寿抗体分泌（血浆）细胞至关重要。Tfh细胞可以与其他CD 4效应细胞区分开;例如，Th 1、Th 2和Th 17亚群（以及其它亚群），通过它们的GC位置和作为B细胞助手的功能。Tfh细胞对于B细胞在正常和自身免疫应答中的帮助是至关重要的;然而，与其他CD 4 T效应细胞亚群相比，这些细胞的发育和功能尚不清楚。为了解决这个问题，我们设计了一种方法，在正常和异常免疫反应期间按时间顺序选择性标记和/或删除这些细胞。为了实现这一目标，我们将利用我们最近的观察，ectodin，骨形态发生蛋白（BMP）的抑制剂，选择性表达的Tfh细胞之间的其他免疫细胞。在这里，我们提出了一个在体内系统的发展，具体目标和操作Tfh细胞使用的ectodin启动子。我们建议制作一种他莫昔芬诱导的Cre小鼠，其中Cre与雌激素受体ERT 2融合，将在ectodin基因（Sostdc 1）的下游表达;靶向构建体已经制成，序列验证，纯化，并显微注射到胚胎干细胞中。当与适当的报道菌株（例如，Rosa-26-YFP）、删除者菌株（R-DTA小鼠）或表达侧翼为两个loxP位点的靶基因的菌株，这将允许我们特异性追踪或消除Tfh细胞，或在免疫或自身免疫应答期间的期望时间点产生基因的Tfh特异性缺失;后者将通过将我们的诱导型Cre小鼠与适当的狼疮倾向菌株杂交来实现。目前，还没有办法特异性靶向和分析Tfh细胞在免疫应答中的作用;因此，我们相信我们创造可诱导的Tfh细胞特异性Cre小鼠的方法将为研究Tfh生物学的不同方面开辟机会。

DESCRIPTION (provided by applicant): CD4 T cell help is crucial for B cell production of antibodies that occurs in germinal centers (GCs) of secondary lymphoid organs (SLOs), a site of immunoglobulin (Ig) affinity maturation and isotype switching. In GCs, T follicular helper (Tfh) cells provide B cells with survival and differentiation signals, including CD40 ligand (CD40), programmed death receptor-1 (PD-1), and IL-21, essential for B cell selection with maturation into memory B cells and long-lived antibody-secreting (plasma) cells. Tfh cells can be distinguished from other CD4 effector cells; e.g., the Th1, Th2, and Th17 subsets (among others), by their GC location and function as B cell helpers. Tfh cells are critical for B cell hel in both normal and autoimmune responses; yet, the development and function of these cells, compared to other CD4 T effector cell subsets, is less clear. To address this issue, we have devised an approach to selectively mark and/or delete these cells chronologically during normal and aberrant immune responses. To accomplish this goal, we will take advantage of our recent observation that ectodin, an inhibitor of bone morphogenetic proteins (BMPs), is selectively expressed by Tfh cells among other immune cells. Here we propose the development of an in vivo system to specifically target and manipulate Tfh cells using the ectodin promoter. We propose to make a tamoxifen-inducible-Cre mouse in which Cre, fused with the estrogen receptor ERT2, will be expressed downstream of the ectodin gene (Sostdc1); the targeting construct has already been made, sequence verified, purified, and micro-injected into embryonic stem cells. When crossed with the appropriate reporter strain (e.g., Rosa-26-YFP), deleter strain (R-DTA mouse) or with strain(s) that expresses a target gene flanked by two loxP sites, it will allow us to specifically track or ablate Tfh cells, or engender a Tfh- specific deletion of genes a desired time points during an immune or autoimmune response; the latter will be accomplished by crossing our inducible Cre mouse with appropriate lupus-prone strains. Currently there is no way to specifically target and analyze the role of Tfh cells in immune responses; thus, we believe our approach of creating an inducible, Tfh cell-specific Cre mouse will open up opportunities to study different aspects of Tfh biology.