B-cell-intrinsic MHCII Signaling is a Diversifying Force of Selection on IgA Repertoires and the Gut Microbiota

B 细胞固有的 MHCII 信号传导是 IgA 库和肠道微生物群选择的多样化力量

基本信息

批准号：
10614060
负责人：
Jason L Kubinak
金额：
$ 40.41万
依托单位：
UNIVERSITY OF SOUTH CAROLINA AT COLUMBIA
依托单位国家：
美国
项目类别：
财政年份：
2021
资助国家：
美国
起止时间：
2021-05-25 至 2026-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10614060
关键词：
Ablation Address Adoptive Transfer Affinity Antibodies Antibody Affinity Antibody Response Antigen Presentation Automobile Driving B-Lymphocytes Benign Bone Marrow CD4 Positive T Lymphocytes Cell Communication Cell Compartmentation Chimera organism Chronic Clone Cells Congenic Mice Data Defect Dependence Ecology Evolution Exons Extravasation Generations Genetic Polymorphism Genetic Variation Genotype Germ-Free Gut associated lymphoid tissue Health Health Promotion Heterozygote Histocompatibility Histocompatibility Antigens Class II Human IL7R gene IgA Deficiency Immune response Immune system Immunoglobulin A Immunologic Memory Individuality Inflammation Integration Host Factors Knowledge Link Lymphocyte MHC Class II Genes Mediating Memory Modeling Mucous Membrane Pathologic Peyer&apos s Patches Phenotype Physiology Plasma Cells Play Population Process Promoter Regions Rag1 Mouse Reaction Role Shapes Signal Transduction Single Nucleotide Polymorphism Map Structure of germinal center of lymph node Surface T-Cell Development T-Lymphocyte Testing Tissues Vertebrates Visual Work antigen binding commensal bacteria congenic density dysbiosis experimental study fitness gut microbiota host microbiota immune activation innovation microbial colonization microbial community microbiota microorganism antigen mouse model novel response systemic inflammatory response

项目摘要

Project Summary T-cell-dependent (TD) immunoglobulin A (IgA) responses regulate the composition of the gut microbiota. How B-cell-intrinsic MHCII signaling, which is central to the development of TD IgA responses, influences host- microbiota interactions is unknown. MHCII is widely assumed to promote clonal diversity in effector lymphocyte populations, but this has not been tested. Here, we present evidence in support of the argument that B cell- intrinsic MHCII signaling controls GC dynamics, IgA repertoire diversity, and microbiota composition. Additionally, evidence from our experiments also indicate that both B-cell-intrinsic ablation of MHCII and specific MHC genotypes are associated with enhanced bacterial dissemination from the gut. Based on these observations and previous work by Dr. Kubinak, this R01 seeks to address the hypothesis that B-cell-intrinsic MHCII signaling is a diversifying force of selection promoting clonal diversity in IgA plasma cell pools and individuality in microbiota composition. The objective of Specific Aim #1 is to define the B-cell-intrinsic role of MHCII during GC reactions in the gut; specifically focusing on its role in shaping plasma cell repertoire diversity. A 'Confetti' mouse model will be used to visually demonstrate the effect of MHCII ablation on GC B cell clonal diversity in the gut. IgH sequencing will be used to determine the effect of MHCII polymorphisms and MHC heterozygosity on IgA repertoire diversity in the gut. scRNA sequencing will be used to determine how MHCII influences overlap in clonal diversity between mucosal and systemic plasma cell pools. RAG1-/- bone marrow (BM) chimeras will be used to quantify the effect of MHCII on cross-seeding of gut-derived plasma cells into the BM. Reciprocal BM chimeras will be used to determine the necessity/sufficiency of defects in B-cell-intrinsic MHCII in regulating bacterial dissemination from the gut. The objective of Specific Aim #2 is to test that microbiota composition is an MHCII-dependent phenotype. RAG1-/- and RAG1-/-IL7R-/- BM chimeras will be used to determine the role gut peyer's patches play in driving MHCII-mediated IgA selection in the gut. Microbial colonization experiments in germfree GF RAG1-/- BM chimeras will determine the effect of B-cell-intrinsic MHCII on IgA-targeting of commensal bacteria. A RAG1-/- adoptive transfer model will be used to determine if MHCII surface density influences IgA-mediated targeting of commensals and microbiota composition. Finally, a novel germfree MHC congenic model will be used to explicitly define the role IgA plays in driving individuality in microbiota composition. Results from these studies will address the B-cell-intrinsic role of MHCII in regulating mucosal IgA responses, microbiota composition, and host health. This is a critical gap in our knowledge that is highly relevant to human health. IgA deficiency is the most common form of antibody-deficiency in humans, is strongly linked to genetic variation in MHCII genes, and has been shown to result in dysbiosis that is associated with chronic inflammation. Experiments outlined here are the first to address how MHC genotype influences microbiota composition and bacterial leakage from the gut, a potent driver of chronic immune activation.

项目概要 T 细胞依赖性 (TD) 免疫球蛋白 A (IgA) 反应调节肠道微生物群的组成。如何 B 细胞固有的 MHCII 信号传导对于 TD IgA 反应的发展至关重要，它影响宿主微生物群相互作用尚不清楚。人们普遍认为 MHCII 可以促进效应淋巴细胞的克隆多样性人群，但这尚未经过测试。在这里，我们提供证据支持 B 细胞- 内在的 MHCII 信号传导控制 GC 动力学、IgA 库多样性和微生物群组成。此外，我们的实验证据还表明，B 细胞固有的 MHCII 消融和特异性 MHC 基因型与肠道细菌传播增强有关。基于这些根据 Kubinak 博士的观察和之前的工作，该 R01 旨在解决 B 细胞固有的假设 MHCII 信号传导是一种多样化的选择力量，可促进 IgA 浆细胞池中的克隆多样性和微生物群组成的个性。具体目标 #1 的目标是定义 B 细胞内在 MHCII 在肠道 GC 反应中的作用；特别关注其在塑造浆细胞库中的作用多样性。 “五彩纸屑”小鼠模型将用于直观地展示 MHCII 消融对 GC B 细胞的影响肠道中的克隆多样性。 IgH测序将用于确定MHCII多态性和MHC的影响肠道 IgA 库多样性的杂合性。 scRNA测序将用于确定MHCII如何影响粘膜和全身浆细胞库之间克隆多样性的重叠。 RAG1-/- 骨髓 (BM) 嵌合体将用于量化 MHCII 对肠道来源的浆细胞交叉接种到 BM。互惠 BM 嵌合体将用于确定 B 细胞固有缺陷的必要性/充分性 MHCII 调节肠道细菌传播。具体目标 #2 的目标是测试微生物群组成是 MHCII 依赖性表型。 RAG1-/- 和 RAG1-/-IL7R-/- BM 嵌合体将用于确定肠道集合淋巴结在驱动肠道中 MHCII 介导的 IgA 选择中所起的作用。微生物无菌 GF RAG1-/- BM 嵌合体中的定植实验将确定 B 细胞固有 MHCII 的作用共生细菌 IgA 靶向。 RAG1-/- 过继转移模型将用于确定 MHCII 是否表面密度影响 IgA 介导的共生体和微生物群组成的靶向。终于有小说了无菌 MHC 同类模型将用于明确定义 IgA 在驱动个体个性中所起的作用微生物群组成。这些研究的结果将阐明 MHCII 在调节中的 B 细胞内在作用粘膜 IgA 反应、微生物群组成和宿主健康。这是我们知识中的一个关键差距与人类健康密切相关。 IgA 缺乏症是人类最常见的抗体缺乏症，与 MHCII 基因的遗传变异密切相关，并已被证明会导致相关的菌群失调伴有慢性炎症。这里概述的实验是第一个解决 MHC 基因型如何影响的实验微生物群组成和肠道细菌渗漏是慢性免疫激活的有力驱动因素。