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: 10209496
• 负责人: DAVID M ROTHSTEIN
• 金额: $ 46.95万
• 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/10209496
• 关键词: Acute; Address; Agreement; Allograft Tolerance; Allografting; Antibody Formation; Autoimmune; Autoimmune Diseases; Autoimmunity; 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细胞起着调节免疫回报的重要作用。小鼠的B细胞缺乏或耗竭可能会担心 自身免疫性并防止同种异体耐受性。我们表明TIM-1是IL-10+调节B的广泛标记 细胞（Bregs）和抗TIM-1通过诱导IL-10+ Bregs诱导耐受性。基于这个发现， 我们的合作者Kuchroo博士刚刚表明，TIM-1调节B细胞上B细胞上的各种抑制分子 除IL-10外，并且专门缺乏B细胞-1的小鼠会出现全身自身免疫性。 这种明确的表明，布雷格在维持耐受性方面起着关键作用。一般而言， 耐受的人类同种异体移植接受者表现出B细胞的“ Breg曲线”和移植术的耗竭 肾脏和心脏移植后分别增加急性排斥和血管病。尽管如此 进步，我们对布雷格的理解仍处于起步阶段。首先，即使是哪个b也没有达成共识 细胞发挥Breg功能，为什么在不同研究中的Bregs属于不同的子集，甚至是否属于 浆细胞（PC）而非B细胞本身，实际上执行了Breg功能。其次，对如何了解 Bregs在体内受到调节，或者可以使用哪些信号来扩展它们。根据我们和我们的合作者的 该提议的进步将直接解决这两个主要差距。该领域受到了阻碍，因为 Bregs很少见，其先前的最佳标记IL-10仅在刺激B细胞后才检测到。 各种B细胞子集的转移可以抑制移植和自身免疫模型的注射。然而， 这些子集是抑制性的，因为它们在给定的 模型，而不是代表真正的布雷格表型。此类子集中只有5-15％的B细胞表达IL-10， 每个子集占所有IL-10+ B细胞的20％。结果，该领域已经确定了无数不同的不同 布雷格“子集”（通常是次要或不成熟），并且对其功能尚无共识。但是，使用IL- 10-GFP记者小鼠，我们最近证明了IL-10+ B细胞可以直接鉴定而无需体外 文化。此外，在蛋白质水平上，规范的卵泡B细胞（FOB），边缘区B细胞（MZB）和PC 每个B-Linege IL-10的约为30％。我们假设属于这些规范子集的Bregs 在SLO中具有独特的本地化，具有不同的功能。在AIM 1中，使用纯化的IL-10+或TIM-1+ 属于这三个子集的布雷格人，我们现在将直接确定它们是相同还是不同的 免疫反应的各个方面（例如体液与细胞）。据报道PC对Breg至关重要 功能，我们发现，由于B细胞特异性缺失，Blimp-1展示了小鼠无法生成PC 受调节的表型，具有改善的同种异体移植存活率和不太严重的EAE，并且两者均显着增加 IL-10+和TIM-1+ Bregs的频率和数量。因此，在AIM 2中，我们将确定如何变化 Blimp-1，PC和微生物群相互作用以调节体内的Breg数字。这项工作将极大地增强我们的 了解B细胞和Breg生物学，并提供与同种异体耐受性高度相关的治疗见解。