Chemokines and Lymphoid Tissue Organization and Function

项目摘要/摘要 生发中心(GC)中的B细胞选择对抗体应答的成功非常重要 流感、HIV-1和许多其他病原体。然而，安装GC所涉及的全套信号 人们不理解他们的反应。最近的工作强调了来自T滤泡辅助者(TFH)的信号的重要性 细胞在驱动高亲和力B细胞优先生长中的作用。决定实力和质量的因素 Tfh细胞和B细胞之间的信号转导还没有完全定义，这是本提案的一个重点。 人类GC来源的淋巴瘤中表面受体hvem(TNFRSF14)频繁突变 滤泡性淋巴瘤和GCB弥漫性大B细胞淋巴瘤)。这一发现表明，HVEM具有重要的 在正常GC功能中的角色，但此角色尚未定义。我们已经发现，HIV缺乏会给B 在GC反应中，细胞与野生型B细胞相比具有竞争优势.我们的初步数据表明 只有当T细胞能够通过表达BTLA来感知HIV时，这种优势才会出现。我们 因此，提出了一个模型，在该模型中，BTLA与TFH细胞的HVEM结合抑制了T细胞Help的量 被送到B细胞。第一个目标将定义HVEM如何抑制B细胞对 在GC中的代表。将使用采用转移和条件删除的方法来确定 B细胞反应的阶段(S)，在这个阶段，HVEM起作用。Hvem胞内结构域的功能将是 逆转录病毒基因转导试验及HIV缺乏症对浆细胞的影响 形成、亲和力成熟和回忆反应将被确定。 第二个目标将定义CD4T细胞内的BTLA如何决定由 B细胞。我们将使用逆转录病毒基因转导来测试BTLA胞浆结构域在TFH细胞中的作用 功能。对缺乏酪氨酸磷酸酶的T细胞SHP1和SHP2的分析将确定它们在BTLA中的作用 功能。将研究HVEM-BTLA结合对细胞-细胞接触和T细胞信号转导的影响 使用活体双光子显微镜结合Salsa6f钙离子报告程序。将遵循ERK信令 使用一种新的核质易位报告小鼠系。 最终目标将检验hvem-btla相互作用的丧失对GC衍生的贡献。 淋巴肿大。我们将测试BTLA是否作为外源性肿瘤抑制因子发挥作用 在T细胞中缺乏BTLA的小鼠中，Bcl2过表达的GC B细胞加速生长。我们将测试 Hvem-和Gna-13缺乏症可能的共同致癌效应。 通过定义HVEM和BTLA如何作用于控制T细胞辅助B细胞反应，这项工作可能指向 促进GC中B细胞多样化和亲和力成熟的新方法。了解如何 HVEM抑制GC B细胞聚集，包括过度表达Bcl2的细胞，将提供可能 为FL和GCB-DLBCL的治疗开辟了新的途径。

Project Summary/Abstract B cell selection in germinal centers (GCs) is important for the success of antibody responses against influenza, HIV-1 and many other pathogens. However, the full set of signals involved in mounting GC responses is not understood. Recent work highlights the importance of signals from T follicular helper (Tfh) cells in driving preferential outgrowth of higher affinity B cells. The factors determining the strength and quality of signaling between Tfh cells and B cells are incompletely defined and are a focus of this proposal. The surface receptor HVEM (TNFRSF14) is frequently mutated in human GC-derived lymphomas (follicular lymphoma and GCB-diffuse large B cell lymphoma). This finding suggests HVEM has an important role in normal GC function but this role has not been defined. We have found that HVEM deficiency gives B cells a competitive advantage over wild-type B cells during GC responses. Our preliminary data suggest that this advantage only occurs when T cells are capable of sensing HVEM through expression of BTLA. We therefore propose a model where HVEM engagement of BTLA on Tfh cells restrains the amount of T cell help delivered to the B cell. The first Aim will define how HVEM restrains the competitiveness of B cells for representation in the GC. Adoptive transfer and conditional deletion approaches will be used to determine the stage(s) of the B cell response at which HVEM acts. The function of the HVEM intracellular domain will be tested using retroviral gene transduction approaches and the effects of HVEM deficiency on plasma cell formation, affinity maturation and recall responses will be determined. The second Aim will define how BTLA within CD4 T cells determines the quality of help received by the B cell. We will use retroviral gene transduction to test the role of the BTLA cytoplasmic domain in Tfh cell function. Analysis of T cells lacking the tyrosine phosphatases, SHP1 and SHP2, will define their roles in BTLA function. The influence of HVEM-BTLA engagement on cell-cell contact and T cell signaling will be studied using intravital 2-photon microscopy combined with the Salsa6f calcium reporter. Erk signaling will be followed using a new nuclear-cytoplasmic translocation reporter mouse line. The final Aim will examine how loss of the HVEM-BTLA interaction contributes to GC-derived lymphomagenesis. We will test whether BTLA functions as an extrinsic tumor suppressor by testing for accelerated outgrowth of Bcl2-overexpressing GC B cells in mice lacking BTLA in T cells. We will test for possible co-oncogenic effects of combined HVEM- and Gna13-deficiency. By defining how HVEM and BTLA act to control T cell help of B cell responses, this work may point to new approaches for augmenting B cell diversification and affinity maturation in GCs. An understanding of how HVEM constrains GC B cell accumulation, including cells over-expressing Bcl2, will provide insights that may lead to new approaches for treatment of FL and GCB-DLBCL.