BASIC MECHANISMS OF GUT MUCOSAL IMMUNE RESPONSES

肠道粘膜免疫反应的基本机制

• 批准号: 2330416
• 负责人: JOHN J CEBRA
• 金额: $ 16.66万
• 依托单位: UNIVERSITY OF PENNSYLVANIA
• 依托单位国家: 美国
• 财政年份: 1994
• 资助国家: 美国
• 起止时间: 1994-05-01 至 1999-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/2330416
• 关键词: B lymphocyte; Peyer's patches; SCID mouse; T lymphocyte; antibody formation; cell cell interaction; cytokine; dendritic cells; gastric mucosa; humoral immunity; immunoglobulin isotypes; intestinal mucosa; mucosal immunity

The need for efficacious mucosal vaccines has received considerably increased attention due to: 1) the rise in antibiotic resistant enteric pathogens and the threat of gram-negative bacterial sepsis; 2) the unexpected cholera epidemics in South America; 3) the prominence of bacterial diarrhea as a killer of infants; 4) the increased incidence of tuberculosis caused by antibiotic-resistant variants; and 5) the continued spread of HIV infections. Because of our still incomplete understanding of certain major features of the mucosal immune response, attempts to develop new mucosal vaccines are still largely empiric. We plan to continue our productive program to understand the mechanisms leading to a mucosal immune response by: 1) trying to elucidate, at cellular and molecular genetic levels, the role of Peyer's patch (PP) (aggregates of lymphoid follicles in the intestinal walls) germinal centers in the development of a humoral mucosal immune response; 2) defining the cell/cell and cell/cytokine exchanges that account for the effectiveness of our B- and T-lymphocyte plus dendritic cell cultures at generating an lgA antibody response; 3) evaluating the contributions of the B2 (follicular) vs. systemic B1 subsets of B cells to protective mucosal immune responses; and 4) analyzing mechanisms that regulate the host's mucosal immune response to enteric gram-negative bacteria and facultative, intracellular gram-positive pathogens, such as Listeria, infecting via the mucosal route. We plan to use germ-free and antigen (Ag)-free mice, which have been very informative for analyzing acute, de novo gut mucosal responses, and a new generation of in vitro functional assays which we have recently developed: 1) the PP and lamina propria tissue fragment assay, which reports the immune status of the gut at the time of tissue sampling; and 2) the single/clonal B cell microculture, which reveals the lg isotype potential, frequency, and physiologic state of Ag-specific B cells. These should permit us to address our aims, for instance by permitting us to quantitate the temporal fluctuations and whereabouts of Ag-specific lgA-memory cells, IgA-pre-plasmablasts, and lgA plasma cells following acute oral stimulation with enteric viruses, bacteria, or toxins. Cross regulation and stimulation of systemic vs. mucosal compartments can also be examined in our system. Finally, we plan to probe how a mucosal response to a novel Ag, given in the context of copious amounts of a wide array of environmental Ags, may differ from the better understood systemic immune response.

对有效粘膜疫苗的需求已大大增加 由于以下原因引起更多关注：1）抗生素耐药性肠道菌群的增加 病原体和革兰氏阴性细菌败血症的威胁； 2） 南美洲意外爆发霍乱疫情； 3) 突出性 细菌性腹泻是婴儿的杀手； 4）发病率增加 由抗生素耐药变异引起的结核病； 5）继续 艾滋病毒感染的传播。 因为我们的理解还不完全 粘膜免疫反应的某些主要特征，试图 开发新的粘膜疫苗在很大程度上仍然是经验性的。我们计划 继续我们富有成效的计划，以了解导致 粘膜免疫反应通过：1）试图阐明细胞和 分子遗传水平，派尔氏淋巴结 (PP)（聚集体）的作用 肠壁中的淋巴滤泡）生发中心 体液粘膜免疫反应的发展； 2）定义 细胞/细胞和细胞/细胞因子交换决定了有效性 我们的 B 淋巴细胞和 T 淋巴细胞以及树突状细胞培养物在生成 IgA抗体反应； 3）评估B2的贡献 （滤泡）与系统性 B1 细胞亚群对保护性粘膜的影响 免疫反应； 4）分析调节宿主的机制 对肠道革兰氏阴性菌的粘膜免疫反应和兼性， 细胞内革兰氏阳性病原体，例如李斯特菌，通过 粘膜途径。 我们计划使用无菌、无抗原 (Ag) 的小鼠， 对于分析急性的、从头的肠粘膜具有非常丰富的信息 反应，以及新一代的体外功能测定，我们 最近开发出：1）PP和固有层组织碎片 检测，报告组织时肠道的免疫状态 采样; 2) 单/克隆 B 细胞微量培养，揭示了 Ag 特异性 B 的 lg 同种型潜力、频率和生理状态 细胞。 这些应该使我们能够实现我们的目标，例如 使我们能够量化时间波动和下落 Ag 特异性 LGA 记忆细胞、IgA 前浆母细胞和 LGA 浆细胞 受到肠道病毒、细菌或急性口腔刺激后 毒素。全身与粘膜的交叉调节和刺激 隔间也可以在我们的系统中进行检查。 最后，我们计划 探究粘膜对新型抗原的反应如何，在以下背景下给出： 大量的各种环境Ag，可能与 更好地了解全身免疫反应。