In Vivo Detection And Mechanisms of Regulatory B cell Function in Transplantation

移植中调节性 B 细胞功能的体内检测和机制

• 批准号: 10393024
• 负责人: DAVID M ROTHSTEIN
• 金额: $ 47.39万
• 依托单位: UNIVERSITY OF PITTSBURGH AT PITTSBURGH
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-07-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10393024
• 关键词: Acute; Address; Agreement; Allograft Tolerance; Allografting; Antibody Formation; Autoimmune; Autoimmune Diseases; Autoimmunity; B-Cell Acute Lymphoblastic Leukemia; B-Cell Development; B-Lymphocyte Subsets; B-Lymphocytes; Biology; Bone Marrow; Cell physiology; Cells; Cellular Immunity; Chronic; Consensus; Detection; Exhibits; Experimental Autoimmune Encephalomyelitis; Frequencies; Funding; Genetic Transcription; Graft Rejection; Graft Survival; Heart Transplantation; Human; Immune; Immune response; Immunity; In Vitro; Inbred Mouse; Inflammation; Interleukin-10; Kidney Transplantation; Knockout Mice; Knowledge; Mediating; Minor; Minority; Modeling; Mus; Phenotype; Plasma Cells; Play; Process; Proteins; Regulation; Regulatory T-Lymphocyte; Reporter; Reporting; Role; Self Tolerance; Signal Transduction; T-Lymphocyte; Therapeutic; Transplant Recipients; Transplantation; Vascular Diseases; Work; allograft rejection; base; cytokine; humoral immunity deficiency; improved; in vivo; infancy; insight; isoimmunity; kidney allograft; loss of function; microbiota; mouse model; mutant; novel; prevent; systemic autoimmunity; targeted treatment; transcriptome sequencing; tumor

B cells play an important role regulating immune responses. B cell deficiency or depletion in mice can worsen autoimmunity and prevent allograft tolerance. We showed that TIM-1 is a broad marker for IL-10+ regulatory B cells (Bregs) and that anti-TIM-1 induces tolerance through induction of IL-10+ Bregs. Based on this discovery, our collaborator Dr. Kuchroo, has just shown that TIM-1 regulates various inhibitory molecules on B cells in addition to IL-10, and that mice specifically lacking B cell-TIM-1 develop spontaneous systemic autoimmunity. This unequivocally demonstrates a critical role for Bregs in maintaining tolerance. In general agreement, tolerant human renal allograft recipients demonstrate a “Breg profile” and peri-transplant depletion of B cells increased acute rejection and vasculopathy after renal and cardiac transplantation, respectively. Despite these advances, our understanding of Bregs remains in its infancy. First, there is no agreement even about which B cells carry out Breg function, why Bregs in different studies belong to different subsets, or even whether plasma cells (PCs), and not B cells per se, actually carry out Breg function. Second, little is known about how Bregs are regulated in vivo, or what signals can be used to expand them. Based on our and our collaborator’s advances, this proposal, will directly address both of these major gaps. The field has been hampered because Bregs are rare and their prior best marker, IL-10, was only detected after stimulation of B cells ex vivo. Transfer of various B cell subsets can inhibit inflammation in transplant and autoimmune models. However, these subsets are suppressive because they contain a relatively high proportion of IL-10+ B cells in a given model, rather than representing a true Breg phenotype. Only 5-15% of B cells in such subsets express IL-10, and each subset comprises <20% of all IL-10+ B cells. As a result, the field has identified a myriad of different Breg "subsets” (often minor or immature), and there is no consensus as to their function. However, using IL- 10-GFP reporter mice, we recently demonstrated that IL-10+ B cells can be directly identified without in vitro culture. Moreover, on a protein level, canonical Follicular B cells (FOB), Marginal Zone B cells (MZB) and PCs each account for ~30% of all B-lineage IL-10. We hypothesize that Bregs belonging to these canonical subsets that have distinct localization in the SLO, have different functions. In AIM 1, using purified IL-10+ or TIM-1+ Bregs belonging to these 3 subsets, we will now directly determine whether they regulate the same or different aspects of the immune response (e.g. humoral vs. cellular). While PCs were reported to be essential for Breg function, we found that mice unable to generate PCs due to B cell-specific deletion of BLIMP-1 exhibit a regulated phenotype with improved allograft survival and less severe EAE, and a marked increase in both frequency and number of IL-10+ and TIM-1+ Bregs. Therefore, in Aim 2, we will identify how changes in BLIMP-1, PCs, and the microbiota interact to regulate Breg numbers in vivo. This work will greatly enhance our understanding of B cell and Breg biology and provide therapeutic insights highly relevant to allograft tolerance.

B 细胞在调节免疫反应中发挥着重要作用，B 细胞缺乏或耗竭会使小鼠的免疫反应恶化。 我们发现 TIM-1 是 IL-10+ 调节 B 的广泛标记。 细胞（Bregs）并且抗TIM-1通过诱导IL-10+Bregs诱导耐受。 我们的合作者 Kuchroo 博士刚刚证明 TIM-1 在 B 细胞中调节各种抑制分子 除了IL-10之外，特别缺乏B细胞-TIM-1的小鼠会产生自发的全身性自身免疫。 这明确地表明了布雷格斯在维持宽容方面的关键作用。 耐受性人类同种异体移植受者表现出肾脏“Breg 特征”和移植周围 B 细胞耗竭 尽管如此，肾移植和心脏移植后的急性排斥反应和血管病变却分别增加。 尽管我们已经取得了进展，但我们对 Bregs 的理解仍处于起步阶段，首先，甚至对于 B 是哪个也没有达成一致。 细胞执行 Breg 功能，为什么不同研究中的 Breg 属于不同的子集，甚至是否 实际上，浆细胞（PC）而不是 B 细胞本身执行 Breg 功能 其次，人们对如何执行 Breg 功能知之甚少。 Bregs 在体内受到调节，或者可以使用哪些信号来扩展它们基于我们和我们的合作者的。 该提案的进展将直接解决这两个主要差距，因为该领域受到了阻碍。 Bregs 很罕见，它们之前最好的标记物 IL-10 仅在离体刺激 B 细胞后才被检测到。 各种 B 细胞亚群的转移可以抑制移植和自身免疫模型中的炎症。 这些亚群是抑制性的，因为它们在给定的细胞中含有相对较高比例的 IL-10+ B 细胞。 模型，而不是代表真正的 Breg 表型，此类亚群中只有 5-15% 的 B 细胞表达 IL-10， 每个子集占所有 IL-10+ B 细胞的比例<20%。因此，该领域已鉴定出无数不同的细胞。 Breg“子集”（通常较小或不成熟），并且对其功能没有达成共识，但是，使用 IL-。 10-GFP报告小鼠，我们最近证明无需体外即可直接识别IL-10+ B细胞 此外，在蛋白质水平上，典型的滤泡 B 细胞 (FOB)、边缘区 B 细胞 (MZB) 和 PC。 每个都占所有 B 谱系 IL-10 的约 30%，我们突袭了属于这些规范子集的 Breg。 在 SLO 中具有不同的定位，在 AIM 1 中使用纯化的 IL-10+ 或 TIM-1+ 具有不同的功能。 Bregs属于这3个子集，我们现在将直接确定它们是否监管相同或不同 据报道，免疫反应的各个方面（例如体液与细胞）对 Breg 至关重要。 功能，我们发现由于 B 细胞特异性删除 BLIMP-1，小鼠无法生成 PC 调节表型，同种异体移植物存活率提高，EAE 严重程度减轻，并且两者均显着增加 因此，在目标 2 中，我们将确定 IL-10+ 和 TIM-1+ Bregs 的频率和数量如何变化。 BLIMP-1、PC 和微生物群相互作用来调节体内 Breg 数量。 了解 B 细胞和 Breg 生物学，并提供与同种异体移植耐受高度相关的治疗见解。