Pre-BCR Function Selecting Novel B Cell Receptors in Chronic Lymphocytic Leukemia

BCR 前功能选择慢性淋巴细胞白血病中的新型 B 细胞受体

• 批准号: 7821003
• 负责人: RICHARD R HARDY
• 金额: $ 47.83万
• 依托单位: RESEARCH INST OF FOX CHASE CAN CTR
• 依托单位国家: 美国
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-30 至 2011-09-29
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7821003
• 关键词: 1 year old; Address; Adult; Adverse effects; Affect; Age; Animals; Antibodies; Antigen Receptors; Antigens; Area; Autoantibodies; B-Cell Development; B-Lymphocytes; BCR gene; Benign; Binding; Biological Assay; Blood Cells; Bone Marrow Cells; Categories; Cell Culture Techniques; Cell Line; Cell Lineage; Cell Proliferation; Cell Separation; Cell surface; Cells; Chronic; Chronic Lymphocytic Leukemia; Clonal Expansion; Complementary DNA; Complex; Country; DNA Sequence Rearrangement; Development; Disease; Electronics; Elements; Employee Strikes; Enhancers; Etiology; Evaluation; Exons; Family member; Fluorescent Antibody Technique; Gene Structure; Generations; Genes; Growth; Human; Human Cell Line; Immunoglobulin Constant Region; Immunoglobulin Variable Region; Immunoglobulins; Incidence; Individual; Investigation; Knowledge; Label; Lead; Leukemic Cell; Lymphocytosis; Malignant Neoplasms; Mature B-Lymphocyte; Measures; Mediating; Modeling; Molecular Conformation; Monoclonal Antibodies; Mus; Mutation; Pathology; Patients; Phenotype; Play; Population; Process; Production; Property; Public Health; Quality of life; RNA; Rag1 Mouse; Receptor Signaling; Receptors, Antigen, B-Cell; Recurrence; Relative (related person); Retroviridae; Rheumatoid Factor; Role; Sampling; Sequence Analysis; Series; Signal Transduction; Site; Splenomegaly; Staging; Stromal Cells; Surface; System; TCL1B gene; Technology; Testing; Time; Transgenic Animals; Transgenic Mice; Work; autoreactive B cell; autoreactivity; base; cell type; experience; expression vector; improved; indexing; insight; interest; leukemia; mouse model; novel; outcome forecast; peripheral blood; public health relevance; receptor function; restriction enzyme; standard care; surrogate light chain

DESCRIPTION (provided by applicant): This application addresses broad Challenge Area (06) Enabling Technologies, and specific Challenge Topic, 06-CA-117: Cancer Development, Pathology, and Pathological Progression. B cell chronic lymphocytic leukemia (CLL) is the most common leukemia affecting adults in Western countries and is recognized by the accumulation of a clonal population of B lineage cells with a surface phenotype distinguishing them from most mature B cells. Although the disorder has been know for over thirty years, surprisingly, its etiology remains unclear and standard treatments, established twenty years ago, entail significant side effects and do not affect a cure, but rather delay progression for a time. In the past ten years it has become clear that CLL can be subdivided into two categories based on extent of mutation of the B cell antigen receptor (BCR): those with significant mutation (>2%) show slower progression and generally a more benign course, whereas those with little mutation have a much worse prognosis and faster progression. Sequence analysis of heavy chain variable regions (VHs) of the BCR has revealed intriguing findings indicating significant VH gene usage biases, and the recurrent usage of similar or even identical CDR3 segments, suggesting a role for selection by common antigens in development of either CLLs or their precursors. There is also clear evidence that CLL BCRs often encode autoreactivity and such self-reactivity may play a key role in the course of disease. Furthermore, recent studies have described the presence of CLL-like monoclonal expansions in relatives of CLL patients, but also more generally in adults over the age of 60. As CLL is a disease whose incidence increase with age, rarely found in young individuals, it is tempting to speculate that clonal B cells often accumulate with age, but only infrequently progress to the CLL stage. Understanding the factors that generate these monoclonal B-cell lymphocytoses (MBLs) and determining how they progress to CLL could lead to breakthroughs in the treatment of CLL. Our interest over the past twenty years has focused on development and characterization of one kind of autoreactive B-cell in the mouse that may model the cell type with a propensity to become MBL and eventually, CLL. These cells, initially identified by expression of CD5 (previously called Ly-1 in mouse), show distinctive localization and functions, importantly being responsible for much of the natural autoantibody production in mice. Some years later, we (and others) showed that production of autoantibody rheumatoid factor was enriched in human CD5+ B-cells. We now think the time is ripe to ask whether generation of the striking biases seen in V genes of BCRs from both mouse and human CD5+ B-cells and CD5+ B-cell leukemias may involve, at least in part, an as-yet un-appreciated mechanism that sculpts the repertoire of natural autoreactive B cells. That is, at the pre-B stage of development, there is strong selection based on assembly of a pre-BCR, and this _-selection checkpoint may be important in understanding the development of distinctive heavy chains with an autoreactive bias. We have developed assays using mouse cells for measuring the capacity of Ig heavy chains to assemble into a pre-BCR and correlated this with the induction of proliferation. We now propose to extend this work, examining heavy chains used in a series of late-developing CLL-like mouse leukemias, but importantly also establishing comparable assays with human cells. This will allow us to assess of pre-BCR assembly and signaling in the human system, and then examine heavy chains from CLL and MBL, to ask whether the distinctive heavy chain biases seen in these cells arise much earlier in development, potentially providing important new insights into the growth and eventual transformation of such cells. Our proposed work will establish the groundwork needed for further study of the role of BCR in development of CLL precursors, eventually uncovering new treatments. Finally, an important aspect of this project is that it will apply our extensive experience and expertise in mouse B cell development, selection, and subsets in a focused study of a potential etiology of a human leukemia, with the potential of developing better, more targeted, therapies. PUBLIC HEALTH RELEVANCE: This project seeks to understand whether chronic lymophocytic leukemias (CLL), the most common leukemia in adults, arises from a distinct set of natural autoreactive B cells, by testing a property of the antibody present on such cells that distinguishes them from other types of B cells. This will be done using a mouse model for CLL, and also by obtaining patient leukemic cells and directly testing their antibodies. The knowledge generated in this study should provide insights into the origins of CLL and lead to the development of new, more targeted, therapies, improving patient quality of life and potentially even providing a cure for this disease.

描述(由申请人提供)：本申请涉及广泛的挑战领域(06)使能技术，以及具体的挑战主题06-CA-117：癌症发展、病理学和病理进展。B细胞慢性淋巴细胞性白血病(CLL)是西方国家最常见的成人白血病，由大量具有不同于大多数成熟B细胞的表面表型的克隆性B细胞群来识别。虽然这种疾病已经知道30多年了，但令人惊讶的是，它的病因仍然不清楚，20年前建立的标准治疗方法会产生显著的副作用，不会影响治愈，而是会推迟一段时间的进展。在过去的十年里，根据B细胞抗原受体(BCR)突变的程度，慢性淋巴细胞性白血病可以细分为两种类型：突变显著(2%)的患者表现为进展较慢，通常病程较良性，而突变较少的患者预后较差，进展较快。对BCR重链可变区(VHS)的序列分析揭示了有趣的发现，表明VH基因存在显著的使用偏差，以及相似甚至相同的CDR3片段的反复使用，这表明共同抗原的选择在CLL或其前体的形成中发挥了作用。也有明确的证据表明，CLL BCR通常编码自身反应性，这种自我反应性可能在疾病过程中发挥关键作用。此外，最近的研究描述了CLL患者亲属中存在CLL样的单克隆性扩张，但更普遍的是在60岁以上的成年人中也存在。由于CLL是一种发病率随年龄增长而增加的疾病，很少在年轻人中发现，因此很容易推测克隆性B细胞经常随着年龄的增长而积累，但很少进展到CLL阶段。了解产生这些单克隆性B细胞淋巴细胞(MBLS)的因素并确定它们是如何进展为CLL的，可能会导致CLL治疗方面的突破。在过去的二十年里，我们的兴趣集中在小鼠体内一种自身反应性B细胞的开发和特征上，这种细胞类型可能会倾向于成为MBL，最终成为CLL。这些细胞最初通过CD5(以前在小鼠中称为Ly-1)的表达来鉴定，显示出独特的定位和功能，重要的是负责小鼠体内大部分天然自身抗体的产生。几年后，我们(和其他人)发现自身抗体类风湿因子的产生在人类CD5+B细胞中得到了丰富。我们现在认为，现在是时候问一问，从小鼠和人类CD5+B细胞和CD5+B细胞白血病的BCR的V基因中看到的显著偏见的产生是否至少在一定程度上涉及到一种迄今尚未被认识的机制，即塑造自然自身反应性B细胞的体系。也就是说，在发育的Pre-B阶段，有基于Pre-BCR组装的强烈选择，并且这个_选择检查点对于理解具有自身反应偏差的独特重链的发展可能是重要的。我们已经开发了使用小鼠细胞的分析方法来测量Ig重链组装成Pre-BCR的能力，并将其与诱导增殖联系起来。我们现在建议扩展这项工作，检查一系列晚期CLL样鼠白血病中使用的重链，但重要的是也要建立与人类细胞的可比性分析。这将使我们能够评估BCR前组装和人类系统中的信号，然后检查CLL和MBL的重链，以询问在这些细胞中看到的独特的重链偏向是否出现在发育的更早阶段，这可能为此类细胞的生长和最终转化提供重要的新见解。我们拟议的工作将为进一步研究BCR在发展CLL前体中的作用奠定必要的基础，最终发现新的治疗方法。最后，该项目的一个重要方面是，它将应用我们在小鼠B细胞开发、选择和亚群方面的丰富经验和专业知识，对人类白血病的潜在病因进行重点研究，并有可能开发更好、更有针对性的治疗方法。 公共卫生相关性：该项目试图通过检测慢性淋巴细胞白血病(CLL)上存在的抗体的特性，将其与其他类型的B细胞区分开来，从而了解慢性淋巴细胞白血病(CLL)是不是由一组不同的自然自身反应性B细胞引起的。这将使用CLL的小鼠模型来完成，也可以通过获得患者的白血病细胞并直接测试它们的抗体来完成。这项研究中产生的知识应该为CLL的起源提供洞察力，并导致新的、更有针对性的治疗方法的开发，提高患者的生活质量，甚至可能提供这种疾病的治疗方法。