IMMUNOSENESCENCE AND ALTERED GERMINAL CENTER RESPONSE

免疫衰老和生发中心反应改变

• 批准号: 6706691
• 负责人: Biao Zheng
• 金额: $ 3.94万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 1999
• 资助国家: 美国
• 起止时间: 1999-07-01 至 2004-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6706691
• 关键词: B lymphocyte; CD95 molecule; T lymphocyte; affinity labeling; age difference; antigen receptors; apoptosis; autoimmunity; cell population study; crosslink; developmental immunology; dissection; flow cytometry; gene rearrangement; gene targeting; genetically modified animals; immune tolerance /unresponsiveness; immunoglobulin genes; immunosenescence; laboratory mouse; lectin; lymphocyte proliferation; receptor expression; recombinase; spleen

The relationship between alteration of germinal center response and immune dysfunction in aging will be studied. In secondary lymphoid organs, germinal centers are sites of post-rearrangement B-cell repertoire modification by V(D)J hypermutation, receptor editing and affinity-driven clonal selection; germinal centers are also necessary for generation of the B-cell memory compartment. Furthermore, our recent work suggests that the germinal center reaction may recapitulate some aspects of primary lymphogenesis and plays a role in the induction and maintenance of self-tolerance in the periphery through selective apoptosis. With in situ and ex vivo approaches, I will test the hypothesis that altered germinal center response plays an important role in immunosenescence, including diminished immune response and heightened autoimmunity. Enzyme- and fluorochrome-labeled antibodies and lectins will be used to characterize and follow the responding lymphocyte populations, especially in reference to germinal centers. BrdUrd- and Tdt-labelling as well as antibodies to apoptosis-associated proteins will be used to study cell proliferation and programmed cell death. Cross-linking reagents for antigen-receptors, steroids and inhibitors for apoptosis will be applied to test the sensitivity and specificity of lymphocyte subpopulations to apoptotic signals. Microdissection of small groups or individual cells from histologic sections and FACS sorting of cell populations will be used in conjunction with various PCR amplification of V(D)J rearrangements, ds RSS breaks, and other gene segments of interest to study the somatic genetics of lymphocytes during the course of aging. These approaches will make possible to systemically study the effect of aging on germinal center response and its consequence.

生发中心反应的改变与衰老中免疫功能障碍的关系将被研究。在次级淋巴器官中，生发中心是通过V(D)J超突变、受体编辑和亲和力驱动的克隆选择进行重排后B细胞谱系修饰的场所；生发中心也是产生B细胞记忆隔间所必需的。此外，我们最近的工作表明，生发中心反应可能概括了原始淋巴发生的某些方面，并通过选择性凋亡在诱导和维持外周的自我耐受中发挥作用。通过原位和体外方法，我将检验生发中心反应改变在免疫衰老中发挥重要作用的假设，包括免疫反应减弱和自身免疫增强。酶和荧光标记的抗体和凝集素将被用来表征和跟踪反应的淋巴细胞群体，特别是在参考生发中心。BrdUrd和TdT标记以及与凋亡相关的蛋白抗体将用于研究细胞增殖和程序性细胞死亡。抗原受体、类固醇和凋亡抑制剂的交联剂将用于测试淋巴细胞亚群对凋亡信号的敏感性和特异性。组织切片中小群或单个细胞的显微解剖和细胞群体的FACS分类将与V(D)J重排、DS RSS断裂和其他感兴趣的基因片段的各种PCR扩增结合使用，以研究淋巴细胞在衰老过程中的体细胞遗传学。这些方法将使系统地研究衰老对生发中心反应的影响及其后果成为可能。