Human B Cell Differentiation in a Model System

模型系统中的人类 B 细胞分化

• 批准号: 6398139
• 负责人: LORI Ruth COVEY
• 金额: $ 22.94万
• 依托单位: RUTGERS, THE STATE UNIV OF N.J.
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-05 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6398139
• 关键词: B lymphocyte; CD antigens; CD38 molecule; CD40 molecule; Epstein Barr virus; biological signal transduction; cell differentiation; cell transformation; child (0-11); cytokine receptors; female; gene expression; gene mutation; gene rearrangement; helper T lymphocyte; human subject; immunodeficiency; immunoglobulin genes; leukocyte activation /transformation; molecular pathology; nuclear factor kappa beta; patient oriented research; tissue /cell culture; transcription factor; tumor necrosis factor alpha

DESCRIPTION (provided by applicant): We have identified a B-cell immunodeficiency that is distinguished by defective responses to CD4O and IL-4 signaling. B-cells from a young female patient (pt#l) have normal expression of CD4O but are clearly deficient in a subset of CD4O-mediated functions including early signals required for switch recombination. However, under specific in vitro conditions pt#1 B-cells can regain functional responsiveness and undergo switching to express downstream antibody classes or isotypes. Our preliminary data support a model whereby a signaling molecule or transcription factor in the CD4O signal transduction pathway leading to NF-kB activation is affected. This hypothesis is supported by our finding that pt#1 B-cells that are transformed by Epstein-Barr virus (EBV) do not express CD23 a cell surface molecule that is critically dependent on the viral latent infection membrane protein LMP)1 and the subsequent activation of NF-kB by this protein. Furthermore, LMP1 usurps the CD4O signaling pathway in order to maintain cell transformation. Surprisingly, the pt#1 EBV-transformed B-cells loose their transforming potential when grown in dilute culture conditions which also suggests that LMP1 activity is compromised. Thus, three related lines of data strongly suggest that the pt#1 defect is located in the CD4O signaling pathway that leads to NF-kB activation and the transcription of specific cellular genes involved in B-cell activation. We propose to use primary and transformed B-cells from pt#1 to characterize the underlying defect Leading to B-cell dysfunction. Efforts will be initially focused on the characterization of TRAF and NF-kB expression and function which are the most proximal and distal signaling events in the CD4O signaling cascade, respectively. The EBV-transformed pt#l B-cells will be used to analyze signaling of LMP1 via the CD4O pathway. Also, these cells will be used in transfection studies that are aimed at complimenting the pt#l defect and in the analysis of of NF-kappaB responsive promoters. Characterization of signaling pathways under the different growth conditions will provide information into the relationship between these signaling pathways and cell transformation. Finally, pt#l T-cells have subtle defects in helper function provided to control B-cells that manifest in inappropriate transcription of the heavy chain locus in response to CD4O signaling alone. Experiments are proposed to understand the basis of this functional defect.

描述（由申请人提供）：我们已经鉴定出一种 B 细胞免疫缺陷，其特征是对 CD4O 和 IL-4 的反应有缺陷 发信号。来自年轻女性患者 (pt#1) 的 B 细胞具有正常表达 CD4O，但明显缺乏 CD4O 介导的功能子集，包括 开关重组所需的早期信号。然而，在具体情况下 体外条件 pt#1 B 细胞可以重新获得功能反应性并进行转换以表达下游抗体类别或同种型。我们的初步 数据支持一个模型，其中信号分子或转录因子 导致 NF-kB 激活的 CD4O 信号转导途径受到影响。 我们的发现支持了这一假设，即 pt#1 B 细胞 Epstein-Barr 病毒 (EBV) 转化的细胞表面不表达 CD23 严重依赖于病毒潜伏感染膜的分子 蛋白 LMP)1 以及该蛋白随后激活 NF-kB。 此外，LMP1 篡夺 CD4O 信号通路以维持细胞 转变。令人惊讶的是，pt#1 EBV 转化的 B 细胞失去了它们的活性。 在稀培养条件下生长时的转化潜力，这也 表明 LMP1 活性受到损害。因此，三个相关的数据行 强烈表明 pt#1 缺陷位于 CD4O 信号通路中 导致 NF-kB 激活和特定细胞基因的转录 参与 B 细胞激活。我们建议使用初级和转换 来自 pt#1 的 B 细胞可表征导致 B 细胞的潜在缺陷 功能障碍。最初的努力将集中在 TRAF 的表征上 以及最近端和远端的 NF-kB 表达和功能 CD4O信号级联中的信号事件分别。这 EBV转化的pt#1 B细胞将用于分析LMP1通过 CD4O途径。此外，这些细胞将用于转染研究 旨在补充 pt#l 缺陷并分析 NF-kappaB 反应性启动子。信号通路的表征 不同的成长条件将为关系提供信息 这些信号通路和细胞转化之间的关系。最后，pt#l T 细胞 用于控制 B 细胞的辅助功能存在细微缺陷 表现为重链基因座响应于不适当的转录 仅 CD4O 信号传导。建议进行实验以了解其基础 功能缺陷。