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

基本信息

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
项目类别：
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

项目摘要

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（AMR）仍然是肾移植失败的主要原因没有批准的治疗方法是提高同种异体移植物长期存活率的关键障碍。通过滤泡辅助 T (Tfh) 细胞进行严格控制了解 Tfh 在肾移植和肾移植中的作用。开发可临床转化的策略来控制 AMR 有望改善长期结果。研究小组已确定 Qa-1（人类 HLA-E）限制性 CD8 Tregs 是 Tfh 的关键调节因子，是 Tfh 的关键调节因子。肾移植中生发中心 (GC) 的 B 细胞分化调节因子受到限制。 <5% 的 CD8 T 细胞表达三联体表面受体——CD44、CD122 和 Ly49。数据（Choi et al. PNAS，2020 年 12 月）和初步数据描述了 CD8 Treg 在调节 Tfh 中的新作用这些 CD8 Tregs 表达识别 Qa-1（一种非经典 Ib 类）的 T 细胞受体 (TCR)。我们发现同种异体反应性激活的 CD4 T 细胞，特别是 Tfh，具有有限的多态性。上调它们的 Qa-1 表达，使它们成为 CD8 Treg 抑制的目标。 (pQa-1)-TCR 通过 Qa-1 基因中的点突变相互作用，同时避免 pQa-1 与抑制物的结合 CD8 Treg 上的 NKG2A 受体导致 Tfh 不受控制的增殖、B 细胞成熟、供体增加特异性抗体（DSA），增加同种异体移植补体激活，并加速同种异体移植排斥。我们的初步数据表明，特定肽 FL9 激动剂可动员和激活 CD8 Treg 抑制 Tfh 依赖性抗移植物抗体介导的损伤并延长完全不匹配的同种异体肾移植物的存活率。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量患者并避免了MHC Ia类多样性的问题，FL9肽治疗AMR具有临床可行性。 AMR 具有很高的转化潜力，并凸显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 细胞激活过程中，同种反应性 T 细胞，主要是Tfh，上调Qa-1-应激肽复合物，主要是其表面的FL9，从而可以通过 Qa1 限制 CD8 Treg 此外，CD8 Treg 上表达的 LY49 充当共抑制信号。对抗原特异性 CD8 Tregs 以及阳性和阴性 T 细胞控制同种异体反应性 T 细胞至关重要的肽对其功能至关重要的信号将导致同种免疫中新的靶向治疗策略，并将为了验证我们的假设，我们开发了多种我们团队独有的新工具。我们还生成了应激肽的超级激动剂，以优化体内 CD8 Tregs 的扩增。新型转基因小鼠，其中 CD8 T 细胞表达特异性识别 FL9-Qa1 肽复合物的 TCR。虽然 LY49 可能对 CD8 Tregs 具有抑制功能，但我们将通过一种新的方法研究其在同种免疫中的作用我们将在实验室中验证这一假设。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。