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.

肾移植中抗体介导的排斥反应（Antibody-mediated rejection，AMR）仍然是导致移植肾丢失的主要原因 这是提高移植物长期存活率的关键障碍。抗体应答 通过T滤泡辅助细胞（Tfh）严格控制。了解Tfh在肾移植中的作用， 开发临床上可转化的策略来控制AMR有望改善长期结果。我们 研究小组已经确定，Qa-1（人类HLA-E）限制性CD 8 T细胞是Tfh的关键调节因子， 肾移植中生发中心（GC）中B细胞分化的调节剂。CD 8 T细胞局限于 <5%的表达三联体表面受体-CD 44、CD 122和Ly 49的CD 8 T细胞。我们最近出版的 数据（Choi et al. PNAS，2020年12月）和初步数据描述了CD 8 Treg在调节Tfh中的新作用， 同种免疫这些CD 8 T细胞表达识别Qa-1的T细胞受体（TCR），Qa-1是一种非经典的Ib类 有限多态性MHC分子。我们发现同种异体反应性活化的CD 4 T细胞，尤其是Tfh， 上调其Qa-1表达，使其成为CD 8 Treg抑制的靶标。破坏肽Qa-1 （pQa-1）-TCR相互作用通过Qa-1基因中的点突变，同时保留pQa-1与抑制性TCR的结合。 CD 8 Treg上的NKG 2A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）、增加的同种异体移植物补体激活和加速的同种异体移植物排斥。 我们的初步数据表明，特异性肽FL 9激动剂对CD 8 Treg的动员和激活作用， 抑制Tfh依赖性抗移植物Ab介导的损伤并延长完全不匹配的肾移植物存活。 由于HLA-E和Qa-1仅表达为2个等位基因中的1个，因此该方法适用于大组患者 避免了MHC Ia类分子多样性的问题。FL 9肽治疗AMR的临床可行性 AMR的高翻译潜力，并强调了这种方法的重要性。 我们的假设是，在肾移植中同种免疫T细胞活化过程中，同种反应性T细胞， 主要是Tfh，上调Qa-1-应激肽复合物，主要是其表面上的FL 9， Qa 1限制性CD 8 Treg。此外，在CD 8 Treg上表达的LY 49充当共抑制信号。识别 通过抗原特异性CD 8 T淋巴细胞控制同种异体反应性T细胞的关键肽， 对它们的功能至关重要的信号将在同种免疫中产生新的靶向治疗策略， 在这里调查。为了验证我们的假设，我们开发了多个我们团队独有的新工具。我们 产生应激肽的超级激动剂以优化体内CD 8 T细胞扩增。我们还生成了一个 新的转基因小鼠，其中CD 8 T细胞表达特异性识别FL 9-Qa 1肽复合物的TCR。 虽然LY 49可能对CD 8 T细胞有抑制作用，但我们将通过一种新的方法来研究其在同种免疫中的作用。 产生敲除小鼠和封闭抗体在我们的实验室开发。我们将测试这个假设， 小鼠肾移植模型，导致细胞和抗体介导的排斥反应，类似于人类排斥反应。