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: 6236028
• 负责人: ANDREW SAXON
• 金额: $ 19.79万
• 依托单位: UNIVERSITY OF CALIFORNIA LOS ANGELES
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-05-01 至 2000-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6236028
• 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.

该提案将确定解释缺陷的机制， 在一个定义的受试者亚组中的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体液免疫的概念， 免疫缺陷的定义子集的CVI受试者反映了失败 的骨髓迁移B细胞能够完成其 以特定的方式发展。 我们的整体 一种假说认为，CVI的这种发育失败反映了 控制替代性教学的信号失调 用于B细胞凋亡、生长或分化的程序。 我们的能力， 从作为该计划赠款的一部分进行的研究中获得， 这些CVI将B细胞置于特定条件下， 不区分，现在提供了测试这一整体的机会 假说. 此外，这些研究还确定了关键的触发因素， (e.g. CD 40、IL-4 R和CD 20），这些细胞因子与改变的 在这个CVI患者子集中的分化结果。 第一个目标 将确定抗CD 40加IL-4刺激如何提供CVI B细胞 有能力最终区分。 我们将研究CD 40 加IL-4对以下B细胞应答的作用：a）预防 细胞凋亡，B）增强生长或c）特异性驱动分化 在导致和不导致分化的条件下。 我们预计， 从而阐明CVI B细胞的关键功能， to be able能够to go on to differentiation区别. 作为这一目标的一部分， 将采用基于PCR的新方法进行mRNA筛选， 确定CD 40加IL-4是否诱导CVI B中的新基因表达 细胞，基因表达所需的CVI B细胞进行 分化 第二个目的是检验c-myc 活性负责将CVI B细胞优先分流到 非分化途径。 我们将测量c-myc的水平， CVI患者的新鲜细胞和细胞系，检测c-myc是否降低 功能拯救CVI B细胞分化功能（例如当 通过IL-4加CD 40刺激），并确定c- 正常B细胞中的myc使细胞分化缺陷。 的 第三个目的将确定CD 20在抑制肿瘤细胞增殖中的作用。 在CVI B细胞中的分化，如果这与改变c-myc 表情 我们将使用激动剂和拮抗剂CD 20 mAb来确定 增强或抑制CD 20功能对B细胞增殖能力的影响 分化或增殖及其与myc表达的关系。 CD 20对myc的刺激将被环孢素A、FK 506和 冈田酸，因为该途径被预测为维持CVI， 分化“缺陷”状态。 我们还将描述 IL-4与CD 40共同驱动CVI B细胞相互关系 分化和CD 20表达和功能的改变。 通过 为了实现上述三个目标，我们打算阐明 导致CVI B细胞无法进行 在体内的生理分化，从而确定 解释B细胞分化失调的机制， 明确定义的伴有固有B细胞的CVI患者子集 异常 这一信息将是重要的， 制定治疗策略， 了解正常人B细胞的发育和分化。