Antigen Specific T Cell Tolerance by Anti CD3 Antibodies

抗 CD3 抗体的抗原特异性 T 细胞耐受

• 批准号: 6742516
• 负责人: CLAUDIO ANASETTI
• 金额: $ 36.68万
• 依托单位: H. LEE MOFFITT CANCER CTR & RES INST
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-05-01 至 2007-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6742516
• 关键词: CD3 molecule; T cell receptor; T lymphocyte; antiantibody; apoptosis; biological signal transduction; bone marrow transplantation; cytokine; flow cytometry; graft versus host disease; helper T lymphocyte; immune tolerance /unresponsiveness; immunosuppression; immunosuppressive; isoantigen; laboratory mouse; leukocyte activation /transformation; ligands; method development; monoclonal antibody; mutant; transplant rejection; transplantation immunology

DESCRIPTION (PROVIDED BY APPLICANT): The long-term goal of this project is to develop methods for induction of peripheral T cell tolerance that could improve prevention of graft rejection and graft-versus-host disease (GVHD) after human marrow transplantation. We propose that by understanding the mechanisms of immunosuppression by anti-CD3-epsilon antibodies in murine models, we will be able to exploit the use of anti-CD3-epsilon antibodies for achieving tolerance in man. Anti-CD3-epsilon F(ab')2 confers a "competence to die" signal to antigen-activated, cycling T cells. T cell death requires both a "competence to die" signal from the TCR or anti-CD3 F(ab')2, and FasL expression induced by prior antigen exposure, or the proximity of FasL+ cells. In mice transplanted with CD8+ TCR transgenic 2C cells specific for the Ld alloantigen, and OT-I cells that are not H2d-reactive, treatment with anti-CD3-epsilon F(ab')2 selectively depleted 2C cells and prevented manifestations of GVHD. Thus, anti-CD3-epsilon antibodies can induce selective immunosuppression by depletion of antigen-activated T cells. Anti-CD3-epsilon F(ab')2 delay but do not prevent rejection of skin grafts, indicating that their efficacy is limited. In vivo modulation of the TCR complex by anti-CD3-epsilon F(ab')2 may limit treatment efficacy and preclude clonal deletion, since activation-induced T cell death requires signaling above a critical threshold of TCRs engaged for sufficient time. We have generated a low avidity anti-CD3-epsilon mutant antibody which activates T cell death over a broader range of concentrations than wild type anti-CD3-epsilon antibody. We will test the hypothesis that low avidity anti-CD3-epsilon antibodies are more efficient at inducing depletion of activated T cells in vivo. Since low avidity peptides can induce T cell apoptosis without cytokine secretion, we have considered the hypothesis that low avidity anti-CD3-epsilon mAb may be unable to induce cytokine secretion, and may be safer in vivo. We present preliminary data that the CD3 and CD4 costimulation provides a positive signal rather than a death signal to pre-activated T cells. By using low avidity anti-CD3-epsilon F(ab')2 mutant antibodies and mutant mouse strains with fyn-/- and lck-/- peripheral T cells, we propose to test the hypothesis that the "compentence to die" signal is transduced through the src tyrosine kinase Fyn rather than Lck. Specific aims are: 1) Design low avidity CD3 ligands with improved immunosuppressive efficacy. 2) Select for low avidity CD3 ligands which induce apoptosis of antigen-activated T cell but no pathogenicity. 3) Define signaling pathways which activate T cell apoptosis in response to CD3 ligation.

描述（由申请人提供）：该项目的长期目标是 开发诱导外周T细胞耐受性的方法，以改善 人类后的预防移植物排斥和移植物抗宿主病（GVHD） 骨髓移植。我们建议通过了解 通过鼠模型中的抗CD3- EPSILON抗体免疫抑制，我们将是 能够利用使用抗CD3- epsilon抗体来实现耐受性 在男人。抗CD3-EPSILON F（AB'）2赋予“死亡能力”信号 抗原激活的循环T细胞。 T细胞死亡需要“ 来自TCR或抗CD3 F（AB'）2的模具”信号，以及由FASL表达 先前的抗原暴露或FASL+细胞的接近度。在移植的小鼠中 与CD8+ TCR转基因2C细胞特有的LD同种抗原，OT-I 抗CD3- epsilon F（AB'）2的细胞不反应性，用抗CD3- epsilon 2 选择性耗尽的2C细胞并防止GVHD的表现。因此， 抗CD3- EPSILON抗体可以通过耗竭诱导选择性免疫抑制 抗原激活的T细胞。抗CD3- epsilon f（ab'）2延迟，但不能阻止 拒绝皮肤移植物，表明其功效受到限制。体内 通过抗CD3-EPSILON F（AB'）2对TCR复合物的调节可能会限制治疗 由于激活诱导的T细胞死亡，功效和排除克隆缺失 需要发出高于临界TCR的临界阈值以获得足够的信号 时间。我们已经产生了低亲和抗CD3- epsilon突变抗体，该抗体 比野生型在更广泛的浓度范围内激活T细胞死亡 抗CD3- EPSILON抗体。我们将检验以下假设： 抗CD3- EPSILON抗体在诱导耗竭的效率更有效 活体活化的T细胞。由于低流行肽可以诱导T细胞 没有细胞因子分泌的凋亡，我们考虑了以下假设。 低自发性抗CD3- epsilon mAb可能无法诱导细胞因子分泌， 并且可以在体内更安全。我们提供了CD3和CD4的初步数据 共刺激提供了正信号，而不是死亡信号 预激活的T细胞。通过使用低自发性抗CD3-EPSILON F（AB'）2突变体 抗体和Fyn - / - 和LCK - / - 周围T细胞的抗体和突变小鼠菌株， 我们建议检验以下假设：“死亡案例”信号是 通过SRC酪氨酸激酶FYN而不是LCK传递。具体目标 是：1）设计低自发CD3配体具有改善的免疫抑制作用 功效。 2）选择诱导凋亡的低相关CD3配体 抗原激活的T细胞，但没有致病性。 3）定义信号通路 这会激活T细胞凋亡，以应对CD3连接。