REGULATION OF B CELL DIFFERENTIATION IN COMMON VARIABLE IMMUNODEFICIENCY--CD40

常见变异免疫缺陷病中B细胞分化的调节--CD40

• 批准号: 5206524
• 负责人: ANDREW SAXON
• 金额: --
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/5206524
• 关键词: B lymphocyte; CD40 molecule; acquired immunodeficiency; apoptosis; biological signal transduction; biomarker; cell differentiation; gene expression; gene induction /repression; human subject; interleukin 4; interleukin 6; laboratory mouse; monoclonal antibody; oncogenes; polymerase chain reaction; surface antigens

This proposal will determine the mechanism that account for the defective B-cell differentiation in a defined subset of subjects with Common Variable Immunodeficiency (CVI). Phenotypic, functional and molecular evidence provided by us and others supports the concept that the humoral immunodeficiency in a defined subset of CVI subjects reflects the failure of bone marrow emigrant B cells to be able to complete their developmental program in a stage specific fashion. Our overall hypothesis is that this developmental failure in CVI reflects the dysregulation of signals that control the alternative instructional programs for B cell apoptosis, growth or differentiation. Our ability, gained from studies undertaken as part of this Program Grant, to examine these CVI subjects B cells under specific conditions where they do or don not differentiate, now provides the opportunity to test this overall hypothesis. Furthermore, these studies have identified key triggers (e.g. CD40, IL-4R and CD20) that are implicated in the altered differentiation outcome in this subset of CVI patients. The FIRST AIM will determine how anti-CD40 plus IL-4 stimulation provides CVI B cells with the ability to ultimately differentiate. We will investigate CD40 plus IL-4 effects on the following B cell responses: a) prevention of apoptosis, b) enhancing growth or c) specifically driving differentiation under conditions that do and do not lead to differentiation. We expect, thereby, to elucidate the critical function CVI B cells require in order to be able to go on to differentiate. As part of this aim, differential mRNA screening using a novel PCR based approach will be employed to determine whether CD40 plus IL-4 induces new gene expression in CVI B cells, gene expression that is required for CVI B cells to undergo differentiation. The SECOND AIM will test the hypothesis that c-myc activity is responsible for preferential shunting of CVI B cells into non-differentiation pathways. We will measure the level of c-myc in our CVI patients' fresh cells and cell lines, test whether decreasing c-myc function rescue CVI B cells differentiative function (e.g. when stimulated by IL-4 plus CD40) and determine if enhanced expression of c- myc in normal B cells renders the cells differentiation defective. The THIRD AIM will determine the role of CD20 in the inhibition of differentiation in CVI B cells and if this is related to altering c-myc expression. We will employ agonist and antagonist CD20 mAbs to determine the effect of enhancing or inhibiting CD20 function on B cells ability to differentiate or proliferate and its relationship to myc expression. CD20 stimulation of myc will be blocked via cyclosporine A, FK506 and okadaic acid as this pathway is predicted to be maintaining CVI in a differentiation 'defective' state. We will also characterize the interrelationship between IL-4 plus CD40 driven CVI B cell differentiation and alterations in CD20 expression and function. By accomplishing the three aims outlined above, we intend to elucidate the mechanisms which lead to the failure of CVI B cells to proceed with physiologic differentiation in vivo and thereby determine the mechanism(s) accounting for the dysregulated B-cell differentiation in a subset of well defined CVI patients with intrinsic B cell abnormalities. This information will be important in ultimately designing therapeutic strategies as well as in providing for increased understanding of the normal human B cell development and differentiation.

这项提案将确定对缺陷的解释机制 常见疾病受试者中特定亚群的B细胞分化 可变免疫缺陷(CVI)。表型、功能和分子 我们和其他人提供的证据支持这样一个概念，即幽默 CVI受试者中特定子集的免疫缺陷反映了这种失败 骨髓迁移的B细胞能够完成其 以特定阶段的方式制定发展计划。我们的整体 假说是CVI的这种发展失败反映了 控制替代指令的信号的失调 B细胞的凋亡、生长或分化的程序。我们的能力， 从作为本计划资助一部分进行的研究中获得的，以检查 这些CVI在特定条件下测试B细胞，在这些条件下，B细胞 没有差异化，现在提供了全面测试这一点的机会 假设。此外，这些研究已经确定了关键的触发因素 (如CD40、IL-4R和CD20) 这一亚组CVI患者的分化结局。第一个目标 将确定抗CD40加IL-4刺激如何提供CVI B细胞 最终具有差异化的能力。我们将调查CD40 外加IL-4对下列B细胞反应的影响：A)预防 细胞凋亡，b)促进生长或c)特异性地促进分化 在可以和不会导致分化的条件下。我们预计， 因此，为了阐明CVI B细胞所需的关键功能 才能继续进行差异化。作为这一目标的一部分，差异化 利用一种新的基于聚合酶链式反应的方法筛选mRNA将被用于 CD40加IL-4是否诱导CVI B细胞新基因表达 细胞，CVI B细胞所需的基因表达 差异化。第二个目标将检验c-myc基因的假设 活性负责CVI B细胞优先分流到 无分化途径。我们将测量c-myc在我们的 CVI患者新鲜细胞和细胞系，检测c-myc是否降低 功能挽救CVI B细胞分化功能(例如当 IL-4加CD40刺激)，并确定c- 正常B细胞中的MYC导致细胞分化障碍。这个 第三，AIM将确定CD20在抑制血管紧张素转换酶中的作用 CVI B细胞的分化及其是否与c-myc改变有关 表情。我们将采用激动剂和拮抗剂CD20单抗来确定 增强或抑制CD20功能对B细胞功能的影响 分化或增殖及其与myc表达的关系。 CD20对Myc的刺激作用将被环孢素A、FK506和 冈田酸作为这一途径被预测为在 分化“缺陷”状态。我们还将描述 IL-4+CD40诱导的CVI B细胞的相互关系 CD20的表达和功能的分化和改变。通过 为了达到上述三个目标，我们打算阐明 导致CVIB细胞不能继续进行的机制 体内的生理分化，从而决定了 B细胞分化异常的机制(S) 具有固有B细胞的明确CVI患者的一个亚群 异常现象。这些信息最终将是重要的 设计治疗策略以及为增加 了解人类正常的B细胞发育和分化。