SUPPRESSION OF T CELL RESPONSES BY ANTI-MHC ANTIBODIES

抗 MHC 抗体抑制 T 细胞反应

• 批准号: 6234968
• 负责人: E STEVE WOODLE
• 金额: $ 10.03万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-09-01 至 1998-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6234968
• 关键词: CD8 molecule; MHC class I antigen; T cell receptor; T lymphocyte; antibody receptor; apoptosis; artificial immunosuppression; biological signal transduction; cell cycle proteins; cytokine; immunoprecipitation; laboratory mouse; monoclonal antibody; phosphorylation; tissue /cell culture; transplant rejection

Although significant advances were achieved in clinical immunosuppression in the early 1980's, recently developed immunosuppressive agents such as FK 506 and mycophenolate mofetil have had relatively little impact on the problem of graft rejection. In addition, although several new immunosuppressive monoclonal antibodies (mAbs) have been tested clinically, none has been shown to possess efficacy superior to OKT3. Our laboratory has developed several new mAbs that possess potent T cell inhibition properties. The proposed research focuses on development of the most promising of these mAbs. This mAb, 5H7, is an anti-human Class MHC mAb that differs from other anti-MHC mAbs in that it binds exclusively to a monomorphic determinant of the alpha3 domain. Experience with this mAb has provided the initial evidence that anti-Class I MHC mAbs act directly at the level of the responding T cell in suppressing cellular responses. This mAb is also a potent inducer of apoptosis in peripheral blood lymphocytes, thus confirming previous observations in mice with alpha3 domain-specific anti-Class l mAbs. Recent studies have demonstrated that TCR signaling augments apoptosis mediated by 5H7 mAb. The proposed studies will provide a fundamental understanding of the mechanisms by which this mAb suppresses T cell responses and induces apoptosis in lymphocytes. The effects of 5H7 on T cell signaling with particular attention to early protein phosphorylation events will be determined. The role of accessory cells in 5H7-mediated suppression of T cell responses will be examined by dissecting individual effects of 5H7 binding to T cell class I molecules, accessory cell class I molecules, and accessory cell Fc receptors using digest fragment preparations of 5H7 and control mAb, and specific types of accessory cells. The apoptosis-inducing properties of 5H7 will also be investigated. The sensitivity of individual T cell subsets to 5H7-induced apoptosis will be determined. Other proteins known to regulate apoptosis in lymphocytes (Fas, Fas ligand, Bcl-2, Bcl-x) will be examined for possible participation in 5H7-induced apoptosis. The nature of TCR- mediated enhancement of 5H7-induced apoptosis will be examined by dissecting the role of TCR and class l signaling strength in the induction of apoptosis. T cell subsets will be targeted for in vivo depletion (by combined treatment with 5H7 and anti-Vbeta mAb), including antigen- specific alloreactive T cells (by combined treatment with 5H7 and alloantigen).

尽管临床免疫抑制取得了重大进展 20世纪80年代初，新近开发的免疫抑制剂如 FK 506 和吗替麦考酚酯对 移植物排斥反应的问题。 此外，虽然有几项新 免疫抑制单克隆抗体（mAb）已经过测试 临床上，没有一种药物被证明具有优于 OKT3 的功效。我们的 实验室开发了几种具有强效T细胞的新型单克隆抗体 抑制特性。拟议的研究重点是开发 这些单克隆抗体中最有前途的。该单克隆抗体 5H7 是一种抗人类 MHC 类 mAb 与其他抗 MHC mAb 的不同之处在于它专门结合 α3结构域的单态决定簇。使用该单克隆抗体的经验 提供了抗 I 类 MHC 单克隆抗体直接发挥作用的初步证据 在应答 T 细胞水平上抑制细胞反应。 该 mAb 也是外周血细胞凋亡的有效诱导剂 淋巴细胞，从而证实了之前在 α3 小鼠中的观察结果 域特异性抗 l 类单克隆抗体。最近的研究表明 TCR 信号传导增强 5H7 mAb 介导的细胞凋亡。拟议的研究 将提供对这一机制的基本理解 mAb 抑制 T 细胞反应并诱导淋巴细胞凋亡。这 5H7 对 T 细胞信号传导的影响，特别注意早期 将确定蛋白质磷酸化事件。配件的作用 5H7 介导的 T 细胞反应抑制中的细胞将通过以下方法进行检查 剖析 5H7 与 T 细胞 I 类分子结合的个体效应， 辅助细胞 I 类分子和辅助细胞 Fc 受体使用 5H7 和对照 mAb 的消化片段制剂，以及特定类型的 辅助细胞。 5H7 的细胞凋亡诱导特性也将是 调查了。个体T细胞亚群对5H7诱导的敏感性 将测定细胞凋亡。其他已知调节细胞凋亡的蛋白质 将检查淋巴细胞（Fas、Fas 配体、Bcl-2、Bcl-x）中的 可能参与5H7诱导的细胞凋亡。 TCR 的性质- 5H7 诱导的细胞凋亡介导的增强将通过以下方法进行检查 剖析 TCR 和 l 类信号强度在诱导中的作用 细胞凋亡。 T 细胞亚群将被靶向体内耗竭（通过 5H7 和抗 Vbeta mAb 联合治疗，包括抗原- 特异性同种反应性 T 细胞（通过与 5H7 和 同种异体抗原）。