STUDIES OF PRIMARY IMMUNODEFICIENCY DISEASES

原发性免疫缺陷疾病的研究

• 批准号: 5200518
• 负责人: W STROBER
• 金额: --
• 依托单位: NATIONAL INSTITUTE OF ALLERGY AND INFECTIOUS DISEASES
• 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/5200518
• 关键词: B lymphocyte; T lymphocyte; cell cell interaction; gene therapy; human genetic material tag; human subject; hypogammaglobulinemia; immunodeficiency; immunogenetics; immunoglobulin genes; immunopathology; leukocyte activation disorder; leukopoiesis; lymphocyte proliferation; protein tyrosine kinase; tissue /cell culture; transfection; transfection /expression vector

Studies in our laboratory have focused on defining the nature of the B cell and T cell defects in Common Variable Immunodeficiency (CVI), a primary acquired human immunodeficiency state characterized by hypogammaglobulinemia and impaired functional antibody responses. Previous studies of purified B cells of patients with CVI show that although the cells have a normal capacity to proliferate, they manifest differentiation defects at multiple levels. Thus, as compared with normal B cells, circulating CVI B cells contain reduced numbers of sIgG+ and sIgA+ cells with a commensurate increase in sIgM+ B cells, suggesting an in vivo defect in isotype switch. In addition, they fail to undergo differentiation into immunoglobulin-producing cells. We now have shown that these defects are associated with the ability of CVI B cells to upregulate and sustain high level surface expression of a critical T cell ligand, B7-2. We have found that CVI B cells, under a variety of stimulatory conditions manifest premature upregulation of B7-1, a surface molecule now thought to inhibit B cell-T cell interaction. These abnormalities of cell surface B7 expression area a likely explanation of the fact that CVI B cells are relativiely poor antigen presenting cells (APC). Thus, purified CVI B cells are less efficient APC when compared to normal B cell of PHA-stimulated T cells using IL-2 as a read-out of T cell stimulation. Moreover, this deficiency is corrected by the addition of anti-CD28 antibody, i.e., an antibody that replicates the function of B7. Overall, these data provide evidence that B cell function in CVI is abnormal in a way that is quite separate from the known immunoglobulin production deficit. A second area of focus in immunodeficiency concerns X-linked agammaglobulinemia (XLA), another major humoral immunodeficiency syndrome. In this disease, B cell development is arrested at the pre-B cell stage and there is an absence of mature B cells. This abnormality results from mutation in a gene, the btk gene whose product is a key tyrosine kinase in B cell activation. In the present study we have prepared a retroviral vector containing a btk cassette and have used this vector to transfer btk into NIH 3T3 fibroblasts. If this vector is producing btk protein, as determined by tyrosine kinase activity, we will be in a position to transfect patient CD34+ cells with the retroviral vector.

我们实验室的研究集中在定义B的性质上 常见变异型免疫缺陷（CVI）中的细胞和T细胞缺陷， 原发性获得性人体免疫缺陷状态，特征为 低丙种球蛋白血症和功能性抗体应答受损。 先前对CVI患者的纯化B细胞的研究表明， 尽管细胞具有正常的增殖能力， 多层次的差异化。 因此，与 正常B细胞、循环CVI B细胞含有减少的sIgG+ sIgA+细胞与sIgM+ B细胞相应增加，提示 同种型转换的体内缺陷。 此外，他们不接受 分化为免疫球蛋白产生细胞。 我们现在已经展示了 这些缺陷与CVI B细胞 上调并维持关键T细胞的高水平表面表达 配体，B7-2。 我们已经发现，在各种条件下，CVI B细胞， 刺激性条件表现出B7-1的过早上调， 现在认为这种分子抑制B细胞-T细胞相互作用。 这些 细胞表面B7表达区的异常可能解释了 CVI B细胞是相对较差的抗原呈递细胞 （APC）。 因此，纯化的CVI B细胞是效率较低的APC， 使用IL-2作为PHA刺激的T细胞的正常B细胞的读数， T细胞刺激。 此外，这一缺陷得到了纠正， 加入抗CD 28抗体，即，一种抗体， B7的功能。 总之，这些数据提供了B细胞 在CVI中的功能是异常的，在某种程度上，这是相当独立的， 已知免疫球蛋白生产缺陷。 第二个重点领域 免疫缺陷涉及X连锁无丙种球蛋白血症（XLA），另一个 严重体液免疫缺陷综合征 在这种疾病中，B细胞 发育停滞在前B细胞阶段， 成熟的B细胞。这种异常是由基因突变引起的， btk基因，其产物是B细胞活化中的关键酪氨酸激酶。 在本研究中，我们制备了一种逆转录病毒载体， btk盒，并已使用该载体将btk转移到NIH 3 T3中 成纤维细胞 如果该载体产生BTK蛋白，如通过 酪氨酸激酶活性，我们将能够检测患者 CD 34+细胞与逆转录病毒载体。