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: 9197259
• 负责人: DAVID M ROTHSTEIN
• 金额: $ 37.74万
• 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 2019-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9197259
• 关键词: Acute; Address; Allograft Tolerance; Allografting; Anatomy; Antigen Presentation; Autoimmune Diseases; Autoimmunity; B-Lymphocyte Subsets; B-Lymphocytes; Biological; Cell physiology; Cells; Collagen-Induced Arthritis; Computer Assisted; Data; Detection; Eragrostis; Exhibits; Experimental Autoimmune Encephalomyelitis; Graft Rejection; Graft Survival; Hour; Human; Humoral Immunities; IgG3; Image; Imagery; Immune response; Immunobiology; Immunofluorescence Immunologic; In Situ; In Vitro; Inflammation; Insulin-Dependent Diabetes Mellitus; Interleukin-10; Knockout Mice; Knowledge; Lead; Locales; Location; Lymphoid; Mediating; Minority; Modeling; Mus; Organ; Phenotype; Plasma Cells; Play; Population; Regulation; Reporting; Role; Shapes; Source; Spleen; Splenic Red Pulp; System; T-Lymphocyte; T-Lymphocyte Subsets; Therapeutic; Time; Tissue imaging; Transplantation; Work; allograft rejection; base; cell motility; chemokine; clinically relevant; cytokine; falls; humoral immunity deficiency; improved; in vivo; insight; kidney allograft; mouse model; novel; prevent; programs; public health relevance; response; simulation

 DESCRIPTION (provided by applicant): It is now clear that B cells play an important role regulating immune responses. B cell deficiency or depletion in mice can worsen autoimmunity and prevent allograft tolerance by various agents thought to target T cells. Moreover, we showed that regulatory B cells (Bregs) can be induced and are responsible for prolonged graft survival mediated by anti-TIM-1. These studies suggest that Bregs play an important role in allograft tolerance. This is echoed by the "B cell profile" observed in tolerant human renal allograft recipients. However, our understanding of Bregs is hampered because they are rare and their only specific marker is IL-10, which thus far, has only been detected after stimulation ex vivo. Transfer of various B cell subsets can inhibit inflammation and prevent allograft rejection in an IL-10 dependent fashion. However, these subsets suppress because they contain the highest proportion of IL-10+ B cells in a given model, rather than representing a true Breg phenotype. Of note, these subsets are generally small (each making up 2-15% of total B cells), and IL-10+ cells are still only 5-15% in each subset. Thus, current studies only account for a minority of IL-10+ B cells. In contrast, <1% of follicular (FO) B cells express IL-10, but because of 50-70% of all B cells are FO B cells, these are a major source of IL-10+ B cells. This has made study of Bregs by transfer of B cell subpopulations challenging, and the solution lies in identifying IL-10+ B cells directly without the need for ex vivo culture and simulation. These same issues have contributed to a remarkable lack of understanding of how Bregs function in vivo. Mice receiving Bregs have largely been treated as a "black box". We do not know which IL-10 + B subsets function as Bregs, where they arise, and how and where they effect suppressor function. Such understanding is key to developing clinically relevant approaches to enhance Breg number and function, and to avoid their inadvertent depletion. We now show that IL-10 expression by B cells can in fact be identified without in vitro simulation, and that most IL-10+ B cells are actually, B1a, MZ, and FO B cells, and even Plasma Cells. Moreover, IL-10+ B cells can be directly visualized in situ. Our lead data confirm that IL-10+ B cells populate the splenic MZ, follicle, and red pulp. Based on these data we now aim to determine how Bregs actually function in vivo to prevent rejection in Breg-dependent allograft models. Different subsets of B cells have different roles and localization within the secondary lymphoid organs (SLO). Therefore in Aim 1 we will determine which IL-10+ B cell subpopulations exhibit the Breg activity and whether different subsets have subspecialized functions. In Aim 2, we will determine where within the SLO Bregs actually act to inhibit the alloimmune response. In Aim 3, we will directly determine whether Bregs suppress T cells through direct cognate interactions. We utilize state of the art imaging and inducible KO mice not previously applied to Breg studies. This work will greatly enhance our understanding of Breg immunobiology and provide therapeutic insights highly relevant to allograft tolerance.