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）：我们已鉴定出一种B细胞 一种以对CD 4 O和IL-4的应答缺陷为特征的免疫缺陷 发信号。来自年轻女性患者（患者#1）的B细胞具有正常的 CD 40，但明显缺乏CD 40介导的功能，包括 切换重组所需的早期信号。然而，具体而言， 体外条件pt#1 B细胞可以重新获得功能性反应， 转换以表达下游抗体类别或同种型。我们的初步 数据支持一种模型，即信号分子或转录因子， 导致NF-κ B活化的CD 4 O信号转导途径受到影响。 这一假设得到了我们发现的支持，即pt#1 B细胞是 EB病毒（EBV）转化的细胞表面不表达CD 23 α 严重依赖于病毒潜伏感染膜的分子 蛋白LMP）1和随后通过该蛋白激活NF-κ B。 此外，LMP 1篡夺了CD 4 O信号传导途径，以维持细胞增殖。 转型令人惊讶的是，pt#1 EBV转化的B细胞失去了它们的 当在稀释培养条件下生长时的转化潜力， 表明LMP 1的活性受到了损害因此，三条相关的数据线 这强烈表明pt#1缺陷位于CD 4 O信号通路中 导致NF-κ B激活和特定细胞基因的转录 参与B细胞活化。我们建议使用原始和转换 来自患者#1的B细胞，用于表征导致B细胞的潜在缺陷 功能障碍最初的工作重点是确定TRAF的特征 和NF-kB的表达和功能，它们是最接近和最远的 CD 40信号级联中的信号事件。的 EBV转化的pt#1 B细胞将用于分析LMP 1通过免疫组织化学的信号传导。 CD 4 O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-κ B 响应式启动子。信号通路的表征 不同的生长条件将提供信息， 这些信号通路和细胞转化之间的联系。最后，PT#1 T细胞 在控制B细胞的辅助功能方面有细微的缺陷， 表现为重链基因座的不适当转录， 单独的CD 40信号传导。提出实验来理解这一点的基础 功能缺陷