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; 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）：我们已经确定了B细胞免疫缺陷，该免疫缺陷通过对CD4O和IL-4的有缺陷的响应而区分 信号。来自年轻女性患者（PT＃L）的B细胞正常表达 CD4O，但显然缺乏CD4O介导的功能的子集 开关重组需要的早期信号。但是，在特定的 体外条件pt＃1 b细胞可以恢复功能响应能力，并经过切换到表达下游抗体类或同种型。我们的初步 数据支持一个模型，在该模型中，信号分子或转录因子在 导致NF-KB激活的CD4O信号转导途径受到影响。 我们发现PT＃1 B细胞是 由爱泼斯坦 - 巴尔病毒转化（EBV）不表达CD23细胞表面 关键取决于病毒潜在感染膜的分子 蛋白LMP）1和该蛋白质随后的NF-KB激活。 此外，LMP1篡夺CD4O信号通路以维护细胞 转型。令人惊讶的是，PT＃1 EBV转换的B细胞松开了 在稀释培养条件下发展时会改变潜力 表明LMP1活性受到损害。因此，三个相关数据行 强烈建议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。我们建议使用主要和转换 从PT＃1的B细胞来表征导致B细胞的潜在缺陷 功能障碍。努力最初将集中在Traf的表征上 NF-KB的表达和功能是最近端和远端 CD4O信号级联中的信号事件。这 EBV转换的PT＃L B细胞将用于分析LMP1的信号 CD4O途径。另外，这些细胞将用于转染研究 旨在称赞PT＃L缺陷和NF-Kappab的分析 响应式启动子。信号通路的表征 不同的增长条件将为关系提供信息 在这些信号通路和细胞转化之间。最后，pt＃l t细胞 提供了为控制B细胞提供的辅助功能的细微缺陷 表现出重链基因座的不适当转录 仅CD4O信号。提出了实验来了解这一点的基础 功能缺陷。