Basic and Translational Mechanisms of Alloimmunization to RBC Transfusion. Project 1

红细胞输注同种免疫的基本和转化机制。

• 批准号: 10711668
• 负责人: JAMES C. ZIMRING
• 金额: $ 40.29万
• 依托单位: UNIVERSITY OF VIRGINIA
• 依托单位国家: 美国
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-10 至 2028-06-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10711668
• 关键词: Affect; Agonist; Alloantigen; Alloimmunization; Antibodies; Antibody Formation; Antibody Response; Antigen-Antibody Complex; Antigens; Antinuclear Antibodies; Autoimmune; B-Cell Activation; B-Cell Antigen Receptor; B-Lymphocytes; Biological; Biological Assay; Biology; Blood Group Antigens; Cell Separation; Chronic; Complication; Data; Dendritic Cells; Development; Disease; Epitopes; Erythrocyte Transfusion; Erythrocytes; Female of child bearing age; Fetus; Genes; Genetic Variation; Glycoproteins; Human; Human Genetics; Immunization; In Vitro; Interferon alpha; Interferons; Isoantibodies; Lead; Leukocytes; Life; Lymphocytosis; Measures; Messenger RNA; Modeling; Monitor; Morbidity - disease rate; Mus; Newborn Infant; Nucleic Acids; Organ; Pathology; Patients; Pattern; Persons; Plasma; Pristane; Production; Reaction; Reticulocytes; Risk; Risk Factors; Role; Sampling; Sickle Cell Anemia; Signal Transduction; System; Systemic Lupus Erythematosus; T-Lymphocyte; TLR2 gene; TLR7 gene; Testing; Therapeutic Intervention; Time; Transfusion; Transgenic Mice; Transgenic Organisms; Translations; Variant; antagonist; cohort; genetic element; genetic predictors; genetic variant; genome wide association study; in vitro testing; in vivo; insight; life-sustaining therapy; mortality; mouse model; novel; novel therapeutics; pre-clinical; prevent; prospective; response; synergism; translational approach

Humoral immunization to alloantigens on red blood cells (RBC alloimmunization) remains a major complication, and in some cases barrier to transfusion therapy for myriad diseases. However, the tendency to become alloimmunized is not evenly distributed; rather, patients tend to become alloimmunized to multiple alloantigens (responders) or none at all despite chronic transfusion (nonresponders). However, the factors that regulate responder vs. nonresponder status remain poorly defined. Rates of RBC alloimmunization is increased in patients with autoimmune pathologies, such as systemic lupus erythematosus (SLE). We have recently discovered that mice with SLE-like biology (i.e. develop anti-nuclear antibodies (ANAs)) have an increased rate of RBC alloimmunization. These mice develop ANAs due to a specific cluster of variant genes (NBA2) that contains multiple orthologues to human genes associated with SLE. Importantly, the NBA2 mice do not display organ pathology associated with SLE, leading to the hypothesis that ANA are an isolated component of SLE that affects RBC alloimmunization. Moreover, in NBA2 mice, toll like receptor 7 (TLR7) and TLR9 are known to regulate ANA formation through mutual antagonism (TLR7 promotes and TLR9 suppresses). These findings lead to the central hypothesis of this project: Central Hypothesis: Anti-nuclear antibodies cause increased RBC alloimmunization through activation of B cells as a result of dysregulated TLR7 and TLR9 signaling. This hypothesis is tested using a novel B cell receptor transgenic mouse that recognizes an authentic human blood group antigen (Kpb epitope) on the human KEL glycoprotein. The anti-Kpb mouse is combined with NBA2 mice that are then transfused with transgenic RBCs expressing the KEL-K2 variant of human KEL, which contains the Kpb antigen. This approach allows an in vivo mechanistic study of early activation and differentiation of naïve B cells specific for an RBC antigen on transfused RBCs. Specific aims 1 and 2 test the role of ANAs on RBC alloimmunization, including the manipulation of TLR7 and TLR9 signaling to rigorously test the central hypothesis. Specific aim 3 uses the human cohort of SCD patients studied in project 4. Patients with SCD have high rates of ANAs. The presence or absence of ANAs in patient plasma will be correlated with patterns of alloimmunization. Patient leukocytes will be stimulated in vitro, in the presence or absence of ANA containing plasma and/or TLR7 and TLR9 agonism or antagonism, using an assay that measures B cell activation and differentiation in response to CD4+ follicular T cell help. Synergy between projects comes from crosstalk between purinergic signaling (project 2) and TLR7 and TLR9, that reticulocytes (project 3) provide agonists for TLR7 and TLR9, and the prediction that genetic variations known to predispose humans to ANA formation will emerge as associations in the prospective GWAS study on RBC alloimmunization in patients with SCD (project 4). The proposed studies have the capacity to both identify novel predictors of RBC alloimmunization (i.e. ANAs) and to provide novel mechanistic insight that can serve as the basis for development of new therapeutics.

对红细胞（RBC同种免疫化）对同种抗原的体液免疫抑制仍然是主要的并发症， 在某些情况下，针对多种疾病输血疗法的障碍。但是，成为 AlloMumumunized均匀分布；相反，患者倾向于将其同种免疫到多种同种抗原 （响应者）或所有目的地的慢性输血（非反应者）。但是，调节的因素 响应者与无响应者状态的定义仍然很差。 RBC同种异体免疫的比率增加 患有自身免疫性病理的患者，例如全身性红斑狼疮（SLE）。我们最近有 发现具有SLE样生物学的小鼠（即开发抗核抗体（ANAS）的小鼠的速率增加 加拿大皇家银行同种免疫。这些小鼠由于特定的变异基因（NBA2）而形成了ANA， 包含与SLE相关的人类基因的多个直系同源物。重要的是，NBA2小鼠不显示 与SLE相关的器官病理学，导致ANA是SLE的孤立成分的假设 影响RBC同种免疫。此外，在NBA2小鼠中，已知像受体7（TLR7）和TLR9一样 通过相互拮抗作用调节ANA形成（TLR7促进和TLR9抑制）。这些发现 导致该项目的中心假设：中心假设：抗核抗体导致RBC增加 由于TLR7和TLR9信号传导失调，通过激活B细胞的激活来免疫。这 使用新型的B细胞受体转基因小鼠测试假设，该小鼠识别正宗人血 人kel糖蛋白上的组抗原（KPB表位）。抗KPB小鼠与NBA2小鼠结合 然后用表达人kel的kel-k2变体的转基因RBC输血，其中包含 KPB抗原。这种方法允许对幼稚B的早期激活和分化的体内机械研究 针对RBC抗原在输血的RBC上具有特异性的细胞。具体目的1和2测试ANA在RBC中的作用 同种免疫，包括对TLR7和TLR9信号的操纵以严格测试中央 假设。特定目标3使用项目4中研究的SCD患者的人数。SCD患者 ANA的比率很高。患者血浆中ANA的存在或不存在将与模式相关 同种免疫。在存在或不存在含有ANA的情况下，患者白细胞将在体外刺激 血浆和/或TLR7和TLR9激动剂或拮抗作用，使用测量B细胞激活和 响应CD4+卵泡T细胞帮助的分化。项目之间的协同作用来自 嘌呤能信号（项目2）和TLR7和TLR9，网状细胞（项目3）为TLR7和 TLR9，并且预测易感人类的遗传变异将出现为 SCD患者的RBC AlloMunization的前瞻性GWAS研究中的关联（项目4）。这 拟议的研究具有识别RBC同种免疫（即ANA）的新型预测指标和 提供新颖的机械洞察力，可以作为开发新疗法的基础。