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: 7936182
• 负责人: RICHARD R HARDY
• 金额: $ 49.27万
• 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/7936182
• 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）使能技术和特定的挑战主题06-CA-117：癌症发展、病理学和病理学进展。B细胞慢性淋巴细胞性白血病（CLL）是西方国家影响成人的最常见白血病，并且通过B谱系细胞的克隆群体的积累来识别，所述细胞具有将它们与大多数成熟B细胞区分开的表面表型。 虽然这种疾病已经被知道了三十多年，但令人惊讶的是，它的病因仍然不清楚，二十年前建立的标准治疗方法带来了显着的副作用，并且不影响治愈，而是延迟了一段时间的进展。在过去的十年中，已经清楚的是，CLL可以基于B细胞抗原受体（BCR）的突变程度被细分为两类：具有显著突变（>2%）的那些显示出较慢的进展并且通常是更良性的过程，而具有很少突变的那些具有更差的预后和更快的进展。 BCR的重链可变区（VH）的序列分析揭示了有趣的发现，表明显着的VH基因使用的偏见，和类似的或甚至相同的CDR 3片段的重复使用，表明共同抗原的选择在CLL或其前体的发展中的作用。 还有明确的证据表明，CLL BCR通常编码自身反应性，这种自身反应性可能在疾病过程中起关键作用。 此外，最近的研究已经描述了CLL样单克隆扩增在CLL患者的亲属中的存在，而且更普遍地在60岁以上的成年人中存在。 由于CLL是一种发病率随年龄增加而增加的疾病，很少在年轻个体中发现，因此很容易推测克隆B细胞通常随年龄积累，但很少进展到CLL阶段。 了解产生这些单克隆B细胞淋巴细胞增多症（MBL）的因素并确定它们如何进展为CLL可能会导致CLL治疗的突破。在过去的二十年里，我们的兴趣集中在小鼠中一种自身反应性B细胞的开发和表征上，该细胞可以模拟具有成为MBL并最终成为CLL的倾向的细胞类型。这些细胞最初通过表达CD 5（以前在小鼠中称为Ly-1）鉴定，显示出独特的定位和功能，重要的是负责小鼠中大部分天然自身抗体的产生。 几年后，我们（和其他人）发现类风湿因子自身抗体的产生在人CD 5 + B细胞中富集。我们现在认为时机已经成熟，可以问一问，在小鼠和人类CD 5 + B细胞和CD 5 + B细胞白血病的BCR V基因中观察到的显著偏差是否可能至少部分涉及一种尚未被认识到的机制，这种机制塑造了天然自身反应性B细胞的库。也就是说，在发育的前B阶段，存在基于前BCR组装的强选择，并且该_选择检查点对于理解具有自身反应性偏好的独特重链的发育可能是重要的。 我们已经开发了使用小鼠细胞测量IG重链组装成前BCR的能力的测定，并将其与增殖诱导相关联。我们现在建议扩展这项工作，检查一系列晚期发展的CLL样小鼠白血病中使用的重链，但重要的是还建立了与人类细胞相当的检测方法。这将使我们能够评估人类系统中的前BCR组装和信号传导，然后检查CLL和MBL的重链，以询问这些细胞中观察到的独特重链偏好是否在发育早期出现，可能为这些细胞的生长和最终转化提供重要的新见解。我们提出的工作将为进一步研究BCR在CLL前体发展中的作用奠定基础，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细胞发育、选择和亚群方面的丰富经验和专业知识，重点研究人类白血病的潜在病因，并有可能开发出更好、更有针对性的治疗方法。 公共卫生关系：该项目旨在了解慢性淋巴细胞白血病（CLL），成人中最常见的白血病，是否源于一组独特的天然自身反应性B细胞，通过测试这些细胞上存在的抗体的特性，将其与其他类型的B细胞区分开来。 这将使用CLL的小鼠模型来完成，并且还通过获得患者白血病细胞并直接测试其抗体来完成。这项研究中产生的知识应该提供对CLL起源的见解，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，甚至可能为这种疾病提供治愈方法。