Evolution of autoreactive GC and epitope spreading in lupus

狼疮自身反应性GC和表位扩散的演变

基本信息

批准号：
10736511
负责人：
Michael Craig Carroll
金额：
$ 48.29万
依托单位：
BOSTON CHILDREN'S HOSPITAL
依托单位国家：
美国
项目类别：
财政年份：
2018
资助国家：
美国
起止时间：
2018-07-13 至 2028-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10736511
关键词：
Adoptive Transfer Affinity Antigens Autoantibodies Autoantigens Autoimmune Diseases Autoimmunity Automobile Driving B-Lymphocytes CD11 Antigens CXCR3 gene Cell surface Cells Chimera organism Clone Cells Complement 3d Receptors Complement Receptor Development Disease Effector Cell Environment Epitope spreading Epitopes Event Evolution Genetic Health ITGAX gene Immunoglobulin-Secreting Cells Kinetics Longitudinal Studies Lupus Lymphoid Malpighian corpuscles Mediating Modeling Mus Nuclear Antigens Pathogenesis Pathology Patients Peptides Phenotype Population Regulation Reporting Role Site Specificity Structure of germinal center of lymph node Systemic Lupus Erythematosus T-Lymphocyte Testing Time autoreactive B cell autoreactivity humoral immunity deficiency migration mouse model mutant novel pathogenic autoantibodies response transcriptomics

项目摘要

Systemic lupus erythematosus (SLE) is an incurable autoimmune disease and represents a substantial health problem in the population. Longitudinal studies of patients and murine models of SLE identify development of autoantibodies against new epitopes over time that correlate with increased pathology. The phenomena is referred to as epitope spreading, i.e. development of autoantibodies against determinants other than the initiating self-antigen. While the mechanism underlying epitope spreading remains unclear, we propose that spontaneous activation of a single B cell clone along with T cell help can promote activation and expansion of multiple distinct clones of nai"ve self-reactive B cells in both GC-dependent and -independent sites where they can be positively selected and undergo affinity maturation, compete and differentiate into effector cells leading to epitope spreading. In order to characterize the dynamics of self-reactive B cells arising in GC-dependent and -independent sites in more depth, we developed a novel adoptive transfer model. In this mouse model, donor B cells from WT or genetic mutants are transferred into lupus mice bearing a single BCR specific for nuclear antigen. We found that the self-reactive WT B cells underwent clonal selection and affinity maturation resulting in single WT clones dominating the GC response much like that observed in our previously reported mixed BM chimeras using the same lupus strain. Remarkably, the donor B cells rapidly expanded over 7 divisions in a GC-independent response that was Tlr 7 and MHC II dependent resulting in selection of a novel subset of effector B cells with a DN2-like phenotype observed in lupus patients (CD11c+CD21 lo). Unexpectedly, donor B cells deficient in CD11c failed to compete with WT donor cells and develop into effector B cells. In the current proposal, we will characterize further the events initiating spontaneous escape of B and T cell tolerance in GC-dependent and -independent responses resulting in epitope spreading. Moreover, we will characterize single TCR that provide functional help in co-stimulation of self-reactive B cells and their antigen specificity. Finally, we will track migration of activated donor cells in the splenic white pulp that give rise to self-reactive effector B cells using a novel spacial transcriptomics approach referred to as MERFISH. Two broad aims are proposed: Aim 1. Characterize the developmental kinetics and functional dynamics of self-reactive extra follicular ASCs. Aim 2. Characterize the role of Tfh cells in epitope spreading of GC-dependent and -independent self-reactive B cells.

全身性红斑狼疮（SLE）是一种无法治愈的自身免疫性疾病，代表了人群的重大健康问题。随着时间的推移，对患者和鼠类SLE的鼠模型的纵向研究确定了针对新表位的自身抗体的发展，这与病理增加相关。该现象被称为表位扩散，即开发自动抗体针对启动自我抗原以外的决定因素。虽然尚不清楚的表位基础的机制尚不清楚，但我们提出，单个B细胞克隆和T细胞的自发激活可以促进NAI的多个不同不同的克隆的激活和扩展。“ ve ve自反应性B细胞在GC依赖性和独立的位点中都可以积极地选择和不足以传播亲密的亲和力和竞争性效果，从而效应效率效应。为了表征在GC依赖性和非依赖性位点中产生的自反应B细胞的动力学，我们开发了一种新颖的继而传递模型。在该小鼠模型中，将来自WT或遗传突变体的供体B细胞转移到具有特异性核抗原的单个BCR的狼疮小鼠中。我们发现，自反应的WT B细胞接受克隆选择和亲和力成熟，导致单个WT克隆主导GC响应，就像我们先前报道的混合BM嵌合体使用相同的狼疮菌株所观察到的那样。值得注意的是，供体B细胞在与GC独立的反应中迅速扩展了7个划分，该反应（TLR 7和MHC II依赖性），导致选择了在狼疮患者中观察到的DN2样表型的新型效应B细胞集（CD11C+CD21 LO）。出乎意料的是，缺乏CD11C的供体B细胞未能与WT供体细胞竞争并发展为效应B细胞。在当前的提案中，我们将进一步表征B和T细胞耐受性在GC依赖性和非依赖性响应中的自发逃脱的事件，从而导致表位扩散。此外，我们将表征单个TCR，该TCR为自反应B细胞及其抗原特异性的共同刺激提供功能帮助。最后，我们将使用新型的空间转录组学方法来跟踪脾白浆中活化的供体细胞的迁移，从而导致自反应效应B细胞。提出了两个广泛的目标：目的1。表征自反应性额外卵泡ASC的发育动力学和功能动力学。 AIM 2。表征TFH细胞在GC依赖性和非依赖性自反应B细胞的表位扩散中的作用。