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: 6477689
• 负责人: CLAUDIO ANASETTI
• 金额: $ 38.69万
• 依托单位: FRED HUTCHINSON CANCER RESEARCH CENTER
• 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/6477689
• 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 细胞耐受的方法，从而改善 预防移植物排斥反应和移植物抗宿主病（GVHD） 骨髓移植。我们建议通过了解其机制 在小鼠模型中通过抗 CD3-ε 抗体进行免疫抑制，我们将 能够利用抗 CD3-ε 抗体来实现耐受 在人身上。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“有能力 来自 TCR 或抗 CD3 F(ab')2 的死亡信号，以及由 先前接触过抗原，或靠近 FasL+ 细胞。在移植的小鼠中 具有对 Ld 同种异体抗原具有特异性的 CD8+ TCR 转基因 2C 细胞和 OT-I 非 H2d 反应性细胞，用抗 CD3-epsilon F(ab')2 处理 选择性耗尽 2C 细胞并预防 GVHD 的表现。因此， 抗 CD3-ε 抗体可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 延迟但不阻止 皮肤移植的排斥反应，表明其功效有限。体内 抗 CD3-ε F(ab')2 对 TCR 复合物的调节可能会限制治疗 功效并防止克隆缺失，因为激活诱导 T 细胞死亡 需要信号高于 TCR 的临界阈值，以充分发挥作用 时间。我们已经产生了一种低亲和力的抗 CD3-ε 突变抗体， 与野生型相比，在更广泛的浓度范围内激活 T 细胞死亡 抗CD3-ε抗体。我们将检验低热情的假设 抗 CD3-ε 抗体可更有效地诱导 体内T细胞被激活。由于低亲合力肽可以诱导 T 细胞 没有细胞因子分泌的细胞凋亡，我们考虑了以下假设： 低亲合力抗 CD3-ε mAb 可能无法诱导细胞因子分泌， 并且在体内可能更安全。我们提供的初步数据表明 CD3 和 CD4 共刺激提供了积极的信号而不是死亡信号 预激活的 T 细胞。通过使用低亲合力抗 CD3-epsilon F(ab')2 突变体 抗体和具有 fyn-/- 和 lck-/- 外周 T 细胞的突变小鼠品系， 我们建议检验“有能力去死”信号的假设 通过 src 酪氨酸激酶 Fyn 而不是 Lck 转导。具体目标 是：1）设计具有改进的免疫抑制作用的低亲合力CD3配体 功效。 2) 选择诱导细胞凋亡的低亲合力CD3配体 抗原激活T细胞但无致病性。 3) 定义信号通路 它响应 CD3 连接而激活 T 细胞凋亡。