The novel role of HLA-E restricted CD8 regulatory T cells in kidney allograft rejection

HLA-E限制性CD8调节性T细胞在肾同种异体移植排斥中的新作用

• 批准号: 10564689
• 负责人: Jamil Azzi
• 金额: $ 68.18万
• 依托单位: BRIGHAM AND WOMEN'S HOSPITAL
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-07-12 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10564689
• 关键词: Acceleration; Agonist; Alleles; Allogenic; Allografting; Antibody Formation; Antibody Response; Antibody Therapy; Antigens; Autoimmunity; B cell differentiation; B-Lymphocytes; Binding; Biology; Blocking Antibodies; CD4 Positive T Lymphocytes; CD44 gene; CD8-Positive T-Lymphocytes; CD8B1 gene; Cell Maturation; Cell Proliferation; Chronic; Clinical; Clustered Regularly Interspaced Short Palindromic Repeats; Complement Activation; Complex; Data; Deposition; Development; E protein; Generations; Genes; Genetic; Genetic Polymorphism; Graft Rejection; Graft Survival; Helper-Inducer T-Lymphocyte; Human; IL2RB gene; Immune response; Infection; Injury; KLRA1 gene; Kidney; Kidney Transplantation; Knock-in Mouse; Knockout Mice; Laboratories; Lymphocytic choriomeningitis virus; Mediating; Modeling; Mus; Mutagenesis; Mutant Strains Mice; Natural Killer Cells; Outcome; Patients; Peptides; Point Mutation; Production; Proliferating; Publishing; Qa-1 Antigen; Regimen; Regulatory T-Lymphocyte; Reporting; Research; Role; Signal Transduction; Specificity; Stress; Structure of germinal center of lymph node; Study models; Surface; System; T-Cell Activation; T-Cell Receptor; T-Lymphocyte; TCR Activation; Testing; Time; Tissue Grafts; Transgenic Mice; allograft rejection; antibody-mediated rejection; antigen test; antigen-specific T cells; clinical translation; clinically relevant; clinically significant; complement C4d; defined contribution; donor-specific antibody; improved; in vivo; isoimmunity; kidney allograft; mouse model; new therapeutic target; novel; novel strategies; pathogen; peptide vaccination; receptor; response; tool; translatable strategy; translational potential; transplant model

Antibody-mediated rejection (AMR) in kidney transplantation remains a major cause of kidney graft loss and a critical hurdle to improve long term allograft survival, with no approved therapy. Antibody responses are tightly controlled through T follicular helper (Tfh) cells. Understanding the role of Tfh in kidney transplant and developing clinically translatable strategies to control AMR holds promise to improve long term outcomes. Our group has identified that Qa-1(HLA-E in human) restricted CD8 Tregs are critical regulators of Tfh, the key modulators of B cell differentiation in the germinal center (GC) in kidney transplantation. CD8 Tregs are confined to <5% of CD8 T cells that express a triad of surface receptors– CD44, CD122 and Ly49. Our recently published data (Choi et al. PNAS, Dec 2020) and preliminary data describe a novel role for CD8 Treg in regulating Tfh in allo-immunity. These CD8 Tregs express T cell receptors (TCRs) that recognize Qa-1, a non-classical class-Ib MHC molecule with limited polymorphism. We show that alloreactive activated CD4 T cells, especially Tfh, upregulate their Qa-1 expression, making them a target for CD8 Treg suppression. Disrupting the peptide Qa-1 (pQa-1)-TCR interaction via a point mutation in the Qa-1 gene while sparing the binding of pQa-1 to the inhibitory NKG2A receptor on CD8 Treg leads to the uncontrolled proliferation of Tfh, B Cell maturation, increased donor specific antibodies (DSA), increased allograft complement activation, and accelerated allograft rejection. Our preliminary data show that mobilization and activation of CD8 Treg by specific peptide FL9 agonists dampen Tfh-dependent anti-graft Ab-mediated injury and prolong fully mismatched kidney allograft survival. Since HLA-E and Qa-1 are expressed as only 1 of 2 alleles, this approach is applicable to large groups of patients and avoids the problems of MHC class Ia diversity. The clinical feasibility of FL9 peptide therapy to AMR has high translational potential in AMR and highlights the significance of this approach. Our hypothesis is that during alloimmune T cell activation in kidney transplantation, alloreactive T cells, primarily Tfh, upregulate Qa-1- stress peptide complexes, mostly FL9 on their surface, allowing tight control by Qa1 restricted CD8 Treg. Furthermore, LY49 expressed on CD8 Treg serve as a coinhibitory signal. Identifying peptides critical for the control of alloreactive T cells by antigen specific CD8 Tregs and the positive and negative signals critical for their function will lead to novel targeted therapeutic strategies in allo-immunity and will be investigated here. To test our hypothesis, we developed multiple new tools that are unique to our group. We generated super agonists for the stress peptides to optimize in vivo CD8 Tregs expansion. We also generated a new transgenic mouse where CD8 T cells express TCR that specifically recognize FL9-Qa1 peptide complex. While LY49 may have inhibitory function on CD8 Tregs, we will study its role in allo-immunity through a newly generated knockout mouse and blocking antibodies developed in our laboratory. We will test this hypothesis in murine kidney transpant model that leads to cellular and antibody mediated rejection similar to human rejection.

肾脏移植中抗体介导的排斥反应（AMR）仍然是肾移植损失的主要原因 也没有批准的疗法，这是改善长期合格生存的关键障碍。抗体反应是 通过T卵泡辅助器（TFH）细胞严格控制。了解TFH在肾脏移植和 制定可转换的策略来控制AMR，这有望改善长期结局。我们的 小组已经确定QA-1（人类中的HLA-E）受限制的CD8 Treg是TFH的关键调节剂， 肾移植中生殖中心（GC）中B细胞分化的调节剂。 CD8 Tregs被限制 表达表面受体的三合会CD44，CD122和LY49的CD8 T细胞中<5％。我们最近出版的 数据（Choi等人PNA，2020年12月）和初步数据描述了CD8 Treg在调节TFH中的新作用 Allo-Immunity。这些CD8 Tregs表达T细胞接收器（TCR），识别QA-1，一种非古典类-IB MHC分子具有有限的多态性。我们表明同种反应性激活的CD4 T细胞，尤其是TFH， 上调其QA-1表达，使其成为CD8 Treg抑制的目标。破坏胡椒QA-1 （PQA-1）-TCR通过QA-1基因中的点突变相互作用，同时避免PQA-1与抑制性的结合 CD8 Treg上的NKG2A受体导致TFH的不受控制的增殖，B细胞成熟，供体增加 特异性抗体（DSA），同种异体移植的完成激活增加并加速同种异体移植排斥。 我们的初步数据表明，特定的胡椒fl9激动剂动员和激活CD8 Treg 抑制TFH依赖性抗移植AB介导的损伤和完全不匹配的肾脏同种异体移植物存活。 由于HLA-E和QA-1仅表示为2个等位基因中的1个，因此此方法适用于大量患者 并避免了MHC类IA多样性的问题。 FL9胡椒疗法对AMR的临床可行性具有 AMR的高转化潜力高，并突出了这种方法的重要性。 我们的假设是，在肾移植中同种异体T细胞激活期间，同种反应性T细胞， 主要TFH，上调QA-1-应力的辣椒络合物，大部分是在其表面上的FL9，可以通过 QA1限制CD8 Treg。此外，在CD8 Treg上表达的LY49用作共抑制信号。识别 抗原特异性CD8 Treg对同种反应性T细胞控制至关重要的肽以及正和阴性 对其功能至关重要的信号将导致新型的靶向治疗策略在异源免疫力中，并且将是 在这里调查。为了检验我们的假设，我们开发了多种新工具，这些工具是我们小组独有的。我们 产生的超级激动剂用于应力辣椒，以优化体内CD8 Tregs膨胀。我们还产生了一个 新的转基因小鼠，其中CD8 T细胞表达特异性识别FL9-QA1 Pepperide复合物的TCR。 尽管LY49可能在CD8 Tregs上具有抑制作用，但我们将通过新的 在我们的实验室中产生的基因敲除小鼠和阻断抗体。我们将在 导致细胞和抗体介导的排斥反应类似于人类排斥反应的鼠肾转移模型。