T CELL REGULATION AND B CELL ACTIVATION

T 细胞调节和 B 细胞激活

• 批准号: 2463766
• 负责人: R J HODES
• 金额: --
• 依托单位: DIVISION OF BASIC SCIENCES - NCI
• 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/2463766
• 关键词: B lymphocyte; CD antigens; CD44 molecule; epitope mapping; helper T lymphocyte; hyaluronate; immunogenetics; immunoregulation; intracellular transport; laboratory mouse; laboratory rat; leukocyte activation /transformation; lipopolysaccharides; monoclonal antibody; neoplasm /cancer transplantation; polymerase chain reaction; protein isoforms; transplantation immunology

PCR analysis has characterized tissue-specific expression of CD44 isoforms resulting from alternative splicing of up to 10 exons. To examine isoform expression at the level of cell surface protein and to probe the possible biological functions of CD44 isoform products in vitro or in vivo, we have generated monoclonal antibodies specific for variable exon products. Immunization with fusion proteins containing variable CD44 exon products produced hybridomas with multiple CD44 variable exon specificities. Flow and immunohistochemical techniques detected variable exon determinants on epithelial cells and on activated lymphocytes. mAbs and fusion proteins are being used to assess the function of CD44 variable isoforms. To identify functional cell surface molecules expressed on activated lymphocytes, mAb were generated by immunizing rats with activated mouse B cells. One of these mAb (GL7) reacts with subpopulations of activated B and T cells, as well as on a functionally distinct subpopulation of CD4+8- thymocytes with unique cytokine secretory capacity and on bone marrow pre-B cells. GL7 administered in vivo influences early B cell development. Expression cloning identified the determinant recognized by GL7 as an alpha 2,6-sialyl transferase-dependent epitope(s) present on human as well as mouse lymphoid cells. Characterization of the activation antigen-specific mAb GL1 led to identification of the mouse B7-2 costimulatory molecule, which has a predominant functional costimulatory role both in vivo and in vitro. Anti-B7-2 mAb inhibited accessory cell-dependent responses of T cells in vitro and in vivo, indicating that B7-2 is a functional costimulatory molecule for T cell-dependent (TD) responses. Expression of B7-2 costimulatory molecules during in vivo TD antibody responses correlated with somatic hypermutation and affinity maturation, and in vivo treatment with anti-B7-2 inhibited TD responses as well as memory formation and somatic mutation. The role of B7-1 and B7-2 in tumor rejection was analyzed using tumor cells transfected with B7-1 or B7-2. Both B7-1 and B7-2 induced tumor injection, and the cytoplasmic domains of these B7 molecules were not required. An essential role of host T cells and of host CD28 was shown by the failure of athymic or CD28- deficient mice to reject B7-transfected tumors.

聚合酶链式反应分析表征了CD44的组织特异性表达 最多10个外显子的选择性剪接产生的异构体。至 在细胞表面蛋白水平上检测异构体的表达 探讨CD44亚型产物可能的生物学功能 无论是在体外还是在体内，我们都已经产生了针对 可变外显子产物。含有以下成分的融合蛋白免疫 CD44可变外显子产物与多个CD44产生的杂交瘤 可变外显子特异性。Flow和免疫组织化学技术 检测到上皮细胞上的可变外显子决定因素 激活的淋巴细胞。单抗和融合蛋白正被用于 评估CD44可变异构体的功能。 鉴定活化的细胞表面表达的功能性分子 用活化的小鼠免疫大鼠产生淋巴细胞、单抗 B细胞。其中一种单抗(GL7)与活化的 B和T细胞，以及在功能上不同的亚群 骨上具有独特细胞因子分泌能力的CD4+8-胸腺细胞 骨髓前B细胞。体内应用GL7对早期B细胞的影响 发展。表达克隆鉴定识别的决定簇 GL7作为α-2，6-唾液酸基转移酶依赖表位(S)的存在 在人和小鼠的淋巴样细胞上。 激活抗原特异性单抗GL1的鉴定 小鼠B7-2共刺激分子的鉴定 在体内和体外发挥主要的功能共刺激作用。 抗B7-2单抗抑制T细胞辅助性细胞依赖反应 在体外和体内，表明B7-2具有功能 T细胞依赖(TD)反应的共刺激分子。表达式 B7-2共刺激分子在体内TD抗体应答中的作用 与体细胞超突变和亲和力成熟相关，并在 抗B7-2体内治疗抑制TD反应和记忆 形成和体细胞突变。B7-1和B7-2在肿瘤中的作用 用转导B7-1或B7-2的肿瘤细胞分析排斥反应。 B7-1和B7-2诱导的肿瘤注射及其胞浆结构域 这些B7分子中的一种是不需要的。宿主T的重要作用 细胞和宿主CD28的失败表现为无细胞或CD28- 缺陷小鼠对B7转基因肿瘤的排斥作用。